I’m sorry this is so distressing to you. Please understand that HOCD (Homosexual Obsessive Compulsive Disorder) is not a DSM 5 diagnosis. (The DSM is the Diagnostic and Statistical Manual that is used by psychologists to name and define psychiatric disorders.) Rather, it is a term that has shown up on the web to describe when a person has unwanted, intrusive thoughts about sexual preference/orientation. It is meant to distinguish between people who are actually heterosexual but are having unwanted obsessive thoughts from people who are in the process of coming out.
I have a problem with the HOCD label for young people. It is normal for young people to question their sexuality. It is normal for you to be somewhat “obsessed” with sex at your age. It is usual for teens to wonder whether feelings for someone of the same sex are a sign of homosexuality. It’s normal to “try on” alternative sexual identities by thinking and fantasizing about what it would be like to be with different people we know and care about. Sometimes it’s difficult to sort out whether feelings are a sign of a deep friendship, a crush, or a romantic attraction. Confusing things still further is that a person’s sexual identity may be uncertain, certain, or fluid over time
I don’t think you are either gay or HOCD. I think you are a normal 18 year old struggling with defining herself in times that see a wide range of sexual behavior as being normal. It is usual to wonder about yourself when what is and isn’t moral or normal is so much less clear than it seemed to be in your parents’ generation. There is recognition now that who people are attracted to is determined by more than hormones and more than genitalia. Who we love is often determined by a complicated combination of biological and psychological reasons as well as our experiences with others.
I suggest you worry less about a label and go with your feelings for now. Over time, you will find out who you are and who you are most comfortable being intimate with. If this continues to trouble you, a few sessions with a licensed therapist may help you delve more deeply into your thoughts and feelings about yourself.
I wish you well.