7 surprising reasons you don't feel happy

Over-thinking what has happened and what is yet to happen can mean you may never drift off into a deep sleep so you don't wake up feeling refreshed and re-energized.

"If you always think about the future and the past, you don't spend time in the moment very much," online psychologist Carolin Müller told Insider.

In a way, happiness is strongly linked to living in the moment, she said. The brain doesn't really know the difference between an emotion you're feeling right now, and one you're re-living in your mind.

"If you think about the situation, you can have all of these feelings from back then come back — you can feel the anger again in your stomach or your chest," said Müller.

"We say it's like a cow, they eat the grass and they bring it up again, and they chew it again, and they swallow it again, and it goes to the next stomach. This is exactly what you're doing. Vomiting it up and chewing it again."

Some people always let their minds jump to the worst possible conclusions, which is known as catastrophic thinking, or "catastrophizing."

Linda Blair, a clinical psychologist and columnist at the Telegraph, told Insider catastrophizing is an unhelpful habit people fall into in some way.

Like any habit, catastrophizing is hard to break, Blair said. Habits are stubborn, and in many cases, people have behaved the same way for years, perhaps decades.

Blair said a bad habit is always ready to jump back into your life, especially when you get highly emotional. But the solution is to learn to be rational and calm.

"You must be kind to yourself and patient, and recognize the more emotional you are the more likely you are to not remember to do it right," Blair said. "Then, when we're still and we're calm, and things are under regulation, we get a chance to be logical."

What you do with negative thoughts you can do with positive ones too, said Müller

"You can think about something really beautiful that happened to you," she said. "How you met someone very nice, or you had a good day at work."

Sometimes, unhappiness can stem from being in the wrong relationship, but fearing the prospect of going it alone. Briana L. Severine, the founder of Sanare Psychosocial Rehabilitation, told Insider there are multiple benefits to being single that people do not always consider.

"There is years of research that show that heterosexual marriage tends to cause slight benefit to men that are not also held by the women in the partnership," Severine said. 

People in relationships may have stopped putting in so much effort to their friendships, which could end up making them feel lonelier than ever. It is a misconception, Severine said, that a romantic partnership prevents those feelings.

"Single people can feel happy and fulfilled in their relationships without having those needs met by a romantic partner," she said. "Just as married people can feel that their social needs are not met, despite having a romantic partner."

Overall, being with the wrong person can have a dire impact on our physical and mental wellbeing. So if there's no medical explanation for the anxiety you feel, it may be time to reexamine your love life and work out if it is healthy or toxic.

Sometimes people can't stop seeing themselves as the victim, Müller said, always asking "why me?" But the reality is, it could happen to anyone, so why not you?

The way to reframe your mind is to stop generalizing, said Müller. For example, if you say everyone is mean to you, really think about whether that's true. In all likelihood, you'll probably be able to find at least one person a day who was nice to you.

"If you see yourself as a victim you make yourself a victim twice because you diminish yourself again," said Müller.

Being scared of spending time alone may mean you have autophobia, or monophobia. People with this diagnosis feel a lot of anxiety when they are left alone, potentially because they have a fear of abandonment that stems from trauma in childhood.

"When you're lonely, you feel unhappy or sad about the quantity or quality of social connections in your life," an article on Cleveland Clinic reads. 

"When you have autophobia, you feel anxious or scared when you're alone or when you think about being alone. You feel this way regardless of how many loved ones and friends are in your life."

For people who do not have this diagnosis, learning to be content with your own company won't just make you happier in the long run, it will also be beneficial for all your future relationships, romantic or otherwise.

"If you understand yourself first of all, you will be able to understand others much more," Müller said. "You'll know about your needs and your expectations, and you will understand why certain people act the way they do."

Overall, if you're feeling down, it's likely to come down to the most basic things, said Müller. For instance, not getting enough sleep, eating badly, not taking care of your relationships.

"See that you have a meaning in your life," she said. "Go out into nature, see more green than concrete, take care of animals and people that are important to you."

There is some evidence diet can impact our mood and wellbeing. Harvard nutritional psychiatrist Dr Uma Naidoo wrote in an article for CNBC that certain foods can cause "anxiety and stress."

For example, eating a lot of industrial seed oils, fried foods, and artificial sweeteners may be linked to a higher risk of depression, while probiotic yogurts, healthy fats in foods like avocados and nuts, and minerals such as iron, magnesium, potassium, and zinc could be good for the brain.

"Keep in mind that changing your diet alone won't help you fully prevent or cure depression and anxiety," Naidoo wrote. "But changing your eating habits can lead to positive effects that leave you feeling energized and rejuvenated."

Müller said the mind is just a tool that helps you make sense of the world.

"Use your mind so that it's useful for you," she said. "And look what it can do, it's amazing, you can solve the most amazing riddle, you can make crossword puzzles and build atomic bombs.

"We can go to Mars because we have a brain and a mind, yet it also leads people to think they are worthless."

If your negative emotions are uncontrolled, you're not the captain of your own ship, and you'll only be able to steer it if you retrain your mind to choose when you want to react.

"It's different from not having emotions, because they are so important for our life," said Müller. "It's more about, do I really want to go there now? Is this reasonable what I'm doing? And thinking maybe not, maybe I can see it from another perspective."