I think I really am a lesbian now. What do you think?

Recently (Actually 4 months now) I've been very depressed. I keep on trying to convinvce myself that I'm straight but at this point I really think I'm a lesbian. I think it started off as HOCD (Or at least all the symptoms are there and I only started doubting myself when I girl said I was a lesbian) It has become harder and harder for me to be able to tell myself that I am straight. I don't believe it anymore. I heard toay that HOCD sufferers shouldn't try to convince themselves they're straight. That they should let thoughts of the same gender corrupt their mind and eventually they will lose interest. But what if I don't lose interest? A few days ago I actually started (Or maybe I was just horny in the first place- I was also mas****ting- so maybe I just got confused that the photos were the only things turning me on) to get turned on by images of heterosexual porn (I hope it wasn't just the girl that was turning me on) and I even became aroused at some pictures of lesbian porn. I'm not very scared that I'm homosexual. If I wasn't homosexual then I would get aroused but stuff like that. I'm scared that if I let myself think lesbian thoughts I will find out that I really am a lesbian (or am I one right now but just avoiding it...) I don't want to tell my parents this. I don't want them to think that I'm a lesbian. I don't want to be a lesbian. I wish I was dead. My family is as poor as dirt. We have a family doctor finally, and I want to make an excuse to see her. But I can't help but think that I really am gay and that whatever help I get from her won't do anything because I really will be gay. Everytime I get this small amount of hope, my thoughts hit me like a tsunami and I'm once again convinced I'm gay. I've asked questions like this repeatedly- I used to find comfort in them but now it's just a useless attempt. It's like I'm pretending to be straight now. I've lost any sign of light in my darkness. If I haven't been going through enough already, just yesterday I feel so greedy now asking God to make me straight. Especially because day before I heard that my grandpa, I said "I'd rather get cancer than doubt my sexuality. I wouldn't mind getting cancer as long as I KNEW and had absolutely no doubts that I was heterosexual." But now I get more and more questions and thoughts. "You're happy being gay. You want to be with girls. You are attracted to girls and boys make you sick." I'm also starting to be convinced that it's only coming out to my parents that I'm upset about. But at first it was only myself and my future I had concern for... but why has it all changed? Also, all this time I continued to ask questions "Am I a lesbian?" on any website I could. I cried everyday and threw up... I tried to take the throwing up ad put it to my advantage. I thought that I could somehow traumatize myself by thiking about women while throwing up. It had the opposite effect and for a long while afterwards think about boys made me feel sick (eventually girls did, too...but now I feel nothingness.) I played constant ridiculous games with myself- trying to predict things (ie I'm straight if my cat licks my hand) to determine things. I use this alot when I'm stressed out about other things. I actually believed it, too, but now it seems that all hope of being heterosexual is lost. I can never accept myself and I don't want anybody else to. I've just given up. I keep on thinking of my parents these days. I know that if I tell them they'll treat me differently and I don't want that. I spend most of my time now up in my room on my netbook thinking about my sexuality. My parents don't understand that I'm really depressed (they don't know anything about this) so I get sent off to school in the morning everyday. Everyday I think about this and try not to burst into tears until I'm in my room.