How To Overcome The Fear Of Being Happy?

Yeah, you sound like me. Whenever there is peace and quiet in my life, my mind starts coming up with ridiculous problems so I have something to do with my time. It’s horrible. And it feels like I have NO control over it.
First, you have to understand that, to different extents, everyone gets crazy, negative thoughts. Some people worry less/ think happy so they’re plagued less. People like me, who always need mental stimulation, come off worse for wear.
You know what I do? I consciously make myself realise that the bad thoughts are in my head. They are not real. They are irrational; they are my fears, and they do not own me.
Then you just don’t think about them. Force yourself to think happy thoughts. Keep yourself extra busy. Tire yourself out so you don’t have the energy for negativity. Working hard is great. For instance, exercise releases endorphins. Endorphins make ya happy. At the very least, when you’re exercising, you’re not worrying about stupid stuff.
Exercise your body! Exercise your mind! Do a puzzle. Talk to a friend. Listen to music and DANCE. All people go through this stuff. Everyone has the ability to get through this stuff. You just have to try!
And remember, happiness is a beautiful thing. Life is so, so short, that it would be a shame to waste it. Life can be tough, too. With all the strife that comes our way sometimes, all the negativity we get from people and circumstances, it wouldn’t be fair for you to do the same thing to yourself. You should be a positive influence in your own life. You can make your own happiness. It’s just a wonderful, glorious state of mind!
Good luck, and take care!

Thinking positively takes conscious effort. Our minds automatically return thoughts to us based on our beliefs. For instance, when something good would happen to me, I used to get scared because I believed that life was cyclical…good was followed by bad. I didn’t believe that things could always go well. Like you, happiness had a tinge of negativity/fear.
I think that affirmations are one of the best ways to change our beliefs. Each day consciously affirm: “I deserve to be happy.” or “I am grateful for my happiness.” Repeat this in your mind each time a negative thought tries to interrupt your positive feelings. After enough repetition, you’ll find that your negative thoughts will be replaced with the thought that you are grateful for feelings of happiness whenever you are happy.