Oh hon, I am so sorry to see you so down and feeling this way.
We all have a reason to live, sometimes it is not revealed to us when we are young, but it does happen for us all i assure you.
You do sound so depressed, St.John's Wart is a good natural medication you could try, and if you still feel no better, perhaps some anti depressant are in order, until you feel yourself again.
As for weight problems, start exercising slowly just a 30 minute walk a day is a good start and it clears the cobwebs from head, heart and soul.
As you can see from the responses there are plenty of us who have felt this way and no what you are going through. Having stumbled into passions was a wise move, you are not alone. You can email myself or any of the above who offered.
Surround yourself with positives good music and GOOD friends, lose the ones, who call you a loser, for they are not true friends at all. Start rebuilding, for now is not the time to give up, you are at the dawning of your life the good times are still to come.
*hugs* email me anytime hon.
A heart and soul are not judged by how much you love, but by how much you are loved by others...
(Goddess - Sovereign of the Spirit)