Why is it so hard to be happy?

I am not sure what it means to be happy. I have always just lived in a space called okay, not bad, and I get by. I see it really hard to be happy. I have always found escapes to cope with not being happy. Either it was video games when I was little and still as an adult. I use food sometimes as a soother as well. I get so down and it takes such energy just to do things to try and keep myself functional and somewhat normal. Trying to be happy is such a chore and always has been. I am not sure if I have that screwed up a personality that it is hard to be happy. I have had and failed at relationships. The last one I was reminded on a daily basis how screwed up my personality was and it didn’t help anymore than the other relationships I had where things died gradually.