Hi I understand you comletely, I'm 15 and I have been feeling the same, I have been searching online for proof that I'm not a Lesbian words like sexuality can change over time or its common for Lesbians to have crushes on boys... these words make me sick I'm not even sure if I'm sraight anymore I think she looks good, then my mind goes crazy.
What reassured me a little was some posts of Lesbians falling for guys, or those Quizzez not the test part but the comments all the girls there go yaaaay I'm a Lesbian, wouldn't I feel the same even in the smallest way, but I know I dont want TO BE HOMOSECTUAL.
Calling it HOCD can make it worse. This isn't really OCD. It's more like a phobia. And the truth is, even if you did it and liked it that alone wouldn't make you a lesbian. We all like sex. We all like orgasms. What makes a person gay is loving people of the same sex. Not just enjoying sex. It's very common to have these kinds of thoughts. They often occur when we're feeling insecure at a young age as you are now. Since it matters not whether or not you're gay, bi, or straight, it only matters because it's bothering you. If you're only attracted to guys, you're straight. If you try it and you like it and want to do it again, I guess you're bi if you're still attracted to guys. But so what? Now, life is harder if you're bi. Hard to maintain a relationship if you can't settle. But the problem you're having is these thoughts are becoming an obsession and bothering you. Not the thoughts themselves. We all have all kinds of thoughts. We don't act on most of them. It's the mind being a mind. If it continues to bother you and you can't shake the obsessive thinking, there's something else going on and you might consider a therapist. They can be seen online. Peace.