I fucked him every position possible for 4+ hours.
You know, that's quite a respectable and fun-sounding way to lose one of your 2 V-cards. You've posted a serious question and I'm not making light of it, I'm being sincere.
For men and women, losing one's virginity, to men or women, is rarely a simple, uncomplicated experience. To answer your question directly, No, you are not gay. You have had a sexual experience (and one that sounds quite fulfilling from a physical standpoint).
Your future sexual experiences and relationships, and the thinking you do after you've had them, will help define whether you (a) want to be labeled at all, or (b) want to be labeled as gay, bi, or straight. It's natural to think about categories right now, but it's too early. As burntserkits said, It just makes you a sexual being…a human. Beautifully put and concise.
Be safe, have fun and explore.
edit/add-on: I just re-read your last post. There's a thread on BL of people' stories about losing their virginity. When you have some time, you might want to check it out. I know that your situation is a bit complicated right now because you had sex with a guy and you're attracted to both sexes. But losing your virginity is a lot to deal with on its own. Most of us play it off like it's nothing.
I lost my virginity long ago. But it was not terribly pleasant. And not terribly awful either. The act was not uncomfortable, but the circumstances and the partner were a cause of shame and discomfort for years (if I chose to think about it). It certainly didn't ruin my sex life and I played it off and moved on quickly.
But I got a lot out of reading the BL thread and I just read it this year. A lot of people do not have a wonderful time the first time they have sex regardless of their sexual orientation. I knew this well, but I still got a lot out of reading the thread.