I am so scared of being gay! Please help! Am I gay? Is this HOCD? What do I do?

Okay, this is long, so please bear with me:

My fear of being gay all started when I was 10 years old. Over the summer, I had a gay experience with another boy. We humped each other penis to penis (I feel disgusted typing this) with clothes on. One day, he came over to my house, and kissed me on the cheek. I felt disgusted and from then on, I stopped hanging out with him, realizing that he was gay. I have no problem with gay people, but that freaked me out.

Anyways, the years passed, and life went on, and I felt pretty good. I have a girlfriend who I love, and I have been chasing girls, and I have a good deal of friends, both male and female. However, over winter break, I recalled the event that happened when I was 10, and I began freaking out about being gay... I've done all these tests to find out if I am gay. Firstly, I am the oldest brother in my family, am left-handed, my ring fingers are slightly longer than my index fingers (approximately 2-3 cm), and I cannot tell if my hair whorl is clockwise or counter-clockwise (I guessed clockwise because it would be more logical since I comb my hair to the right). I have been checking how I walk, how I talk, etc. What freaks me out more about being gay is several things:

- When I was 8,9, and 10, I liked to sing a lot, which I feel is a feminine thing to do. I played with legos, action figures, and hot wheels as a child, but I also enjoyed to sing to various songs, and imagine that I was a star at singing/being in a band. I felt that this was gay, and am freaked out by it. I still sing today, and still imagine being a rockstar or something, but it's just a dream, and in reality, I want to pursue engineering.

- I feel disgusted about what happened when I was ten, but recalling the event gives me a bit of arousal sometimes. I think that this is because back then I had enjoyed the feeling, but I think this could apply to any situation, like if somebody was just humping a pole. I'm really scared of this, though.

- Ever since this obsession about fearing being gay, I am scared to hang out around other males, and normally, when I see a good looking dude, my mind would not think twice, maybe just a thought like "he's a good looking guy; he probably gets a lot of girls," but now, I hear a voice in my head going "oh yeah, he's sexy. he's cute," and I don't want those thoughts because I don't think they're real.

- In my mind, it almost seems like I want to give up and say I'm gay, but I'm not! I don't want to lose all I have, and I don't want to kiss or have sex with another man. I'm so scared of it, and I don't know what to do anymore. Now, with my fear of being gay, I've been painting the whole world gay thinking "oh hey, this famous guy is gay, or this other person is gay. It's not that bad." But then I think "does this mean I'm gay?" And I freak out and cry. I don't know what to do. I've been feeling suicidal and depressed...

I don't want to be gay. It just isn't me. I have a beautiful girlfriend, and I want to be a father with a wife and kids, and I want to raise my children, and go camping, and have sex with my wife, and lead a happy life. I always masturbate to straight porn, and have a few fetishes, but nothing extremely weird/gay. I don't like lesbian porn, really.. I don't know if this is a sign, but I prefer straight porn, but I believe this is because I can relate to the porn more, and fantasize with it better. I just don't want to be gay. I can't imagine living my life with another male, or having sex with another male. I get freaked out by the idea... I just want a normal life... I'm so scared. Please help! What do you think of my situation?