As for the question of "Am I a lesbian?":
This might not be the popular answer, but I would say you're still too young to know for sure -- especially if you haven't even kissed a boy yet! 16 is quite young and, sure, a lot of gay people know they're gay earlier in life, but a lot of people also figure it out during their teen years. So, I don't want to scare you, but it could still be possible -- and so could being bi, or pansexual. Sexuality isn't always so black-and-white, and it can take years to get to know exactly who you are and what you like.
Though, I'd say that after you've made out with a boy or two, your body will probably start to tell you what you like!
As for the question of "Do I have HOCD?":
Well, I'm not a professional, but to me it sounds like your case is more the legitimate (and completely normal!) kind of sexual questioning that a lot of people experience during their youth. However, it can't be denied that you are working yourself into an anxious frenzy over your questioning (and over some *********'s comments about you and your friend), and you are obsessively trying to find an answer to your own questions that you're not going to be able to find until you get a bit more experience with one of both sexes, and that's probably not so healthy.
You might just be more of a thinker than an average girl, or you might be a person who takes other people's small minded and/or stupid comments too seriously, or you could be in the early stages of OCD. Only time will tell.
For now, I think you need to try to relax. You're not going to know anything definitively no matter how many times you ask yourself these questions -- but I agree with the person who said that you need to work on accepting that it doesn't really matter right now anyway. You have plenty of time to figure things out, and just try to remember that what you're going through doesn't mean anything one way or another -- straight people can question their sexuality too! -- and it's completely normal for someone of your age, with little experience, who probably thinks too much ;)
If, however, you were still questioning/obsessing like this, in another year, or two, or three, I would definitely be more worried...
If u r gay it will be exposed when u much younger than u r now. so its very obvious its the anxiety that has made u confused and if u r that kind of person who let away the horses of imaginations then u wil end up worrying that u r a lesbian or bisexual. U r straight & very normal. Stay straight always.
i'm 17...
i started going through the exact same thing when i was 16 and i hate to say it but its been a year and i still haven't figured out if i'm a lesbian. but i've come to realise it doesn't matter! really it doesn't matter and you will eventually fall in love and that persons sex will be irrelevant just don't panic there is no rush to figure it out.