Maybe I don't even know what's going on with my head

Maybe it's going to get worse before it gets better. I seem to have lost interest in everything I'm interested in. I don't even know what to do.. its like.. when I'm happy nothing can bring me down, nothing can stop me. I am on a mission to conquer the world. Everything is fine.. Like I get how I've always been on an emotional high .. I talk super fast, my mind races 100miles a minute.. and then SMASH!! I run into that wall.. 

I cry.. I scream... I fight to breathe.. I can't find my passion for anything, I loose all interest in everything I have ever loved. It all happens to fast.. my heart beats so fast.. and I hate it... Sometimes I just hate hearing my heart beat .. I know that's bad.. I don't know how to fix it.. I just hate my life until I'm suddenly thrown somewhere else and I find something that triggers a happy day... or a happy hour.. Sometimes I'm happy for a couple days.. sometimes a couple hours.. sometimes something that used to make me happy, can make me cry and make me soo angry ...

I'm a mess.. I don't even know.. I can't decide how I really feel.. It's kinda like a roller coaster.. you're going so fast and then BAM... you're going soo slow and life is dragging.. and then BAM... you're on that high again where nothing can bring you down... you're invincible.. but you're really not ... You're a train wreck waiting to happen.. 

I want this to go away... I've been slowly sinking for a few years now.. It's just seemed to all of a sudden hit me.. where I can't function I can't do anything.. I can't even love things I used to love.. you have no idea how that feels.. to not have any emotion towards things that used to never bring you down before.. I can be in the middle of something that used to make me feel soo happy.. something i used to love more than life... and I find myself getting mad at me, because I can't feel anything... I'm numb... And then I hate myself for not enjoying it the way I used to..and then I find myself wondering why I'm even there.. And then when I'm not there... I don't miss it.. WHY!?... Why do I have to go through this.. it's so hard..