I'm On the Pursuit of Happiness

(This isn't part of my 30-prompts list just F.Y.I.)
Ever since I was maybe 15-years-old, I learned something about myself that I knew I was probably going to have to deal with the rest of my life.
I know that there are many skeptics out there who believe depression isn't an illness or it's just something people say they have to use as an excuse for laziness or whatever. But I am someone who struggles with depression ... it scares me like hell.
There have been two times in my life where I have fallen into a deep depression that I had to seek medical help to pull me out. Luckily, my family has always been understanding about my feelings and my struggles. They have never questioned why I can get so sad sometimes and they have always got me the help I needed when I haven't been able to help myself. Those two times were horrible and I don't really know how to describe it other than imagine having someone hanging everything that makes you happy over your head and you jumping as high as you can to yank it away from them but never succeeding.
It's been maybe seven years since I let myself land in a place where I couldn't make myself happy again. But I live in constant fear of when my depression will sneak up on me and pull me under. I know what triggers it and it usually happens when my life abruptly changes or I feel completely crushed by people around me. I'm always on edge when something in my life makes me super sad, because not only am I stressing myself over my sadness, but also worrying if the tides of depression will rise above and drown me.
Another thing that I struggle with is being happy. It takes so much energy for me to be happy, which is supposed to be a natural thing, right? I don't know if that's a symptom of depression, but I feel like I have to work so hard to just be happy. The thing that irritates the heck out of me is that I am blessed with such a great life and I have all the reasons in the world to be extremely happy. I know that makes me selfish and stupid.
I'm trying to be more optimistic and I'm trying to grow up and I'm trying to not let unhappiness hold me back like I have let it. It's affected my relationships and it's held me back from letting people into my life. But it's so hard to do when people can be so disappointing in this world.
The question I ponder is, are a few months of happiness and love worth it if in the end I might have to pay the consequence of dealing with a heartache and sadness that can open the door of depression? Or do I continue to close myself off from people who may offer me love and happiness and choose to live my life in fear of feeling anything because I'm too afraid to feel the one thing that's my kryptonite?
It's been said many a time that life is complicated. And I absolutely agree. I may fall down time and time again, but the beautiful thing I've learned about myself is that I don't give up on life and I know that it will take a thousand years of complete sadness to possibly stop my constant pursuit of happiness. I have hope that I will one day feel content, satisfied and completely happy with the life I've lived.
I will live my life through the pain and struggles as beautifully as I can.