Hi Jessica,
You are experiencing OCD. Denial is actually the opposite of OCD - you say "No, I'm not (whatever thing you are in denial about)" and then you go on your merry way without thinking about it any more.
If you are attracted to boys, then you are heterosexual. If you were also attracted to girls, then you would be bi-sexual, not gay. You said you had a crush on a boy, but have you ever felt that way about a girl?
I saw from your other post that you are only 15, so you may not have had any sexual experiences yet (which is neither good nor bad). That may be part of the source of your anxiety. If you had sex with a boy already and enjoyed the experience, then things might be more clear for you. Part of OCD is experiencing uncertainty. Some people are ok with uncertainty in life and others (like myself) hate it and seek absolute proof that they are one way or another. The problem is life is rarely certain and you have to learn the difference between possibility and PROBABILITY. Is it possible that I may get hit by lightning tonight on my way home? Yes. Is it probable? NO.
Is it possible that you are gay (or bi). Yes. From what you have said, is it probable? NO.
There are various methods to treat OCD. One of the first steps might be to consult a therapist. Is there anyone at your school like a counselor who you could speak to? Do you have a family doctor who could recommend a therapist?
you are suffering from ocd, but these reassurances won't work for you, again your mind will find a loophole and your mind will again start questioning whether you like girls? are you gay?
Its better to consult a psychologist, i know it would be tough for you to talk your parents about ocd but it would be better than suffering from ocd .As you are young in age so you might be given only cognitive behavior therapy as treatment.So you should consult a psychologist.