A gay 15-year-old from Tennessee writes:
"I don't know what just happened! I could SWEAR THAT I'M GAY, but I just went all the way to 3rd base with a girl. Maybe I'm bisexual or pansexual? I'm just very confused and worried and stuff because I've told people that I'm gay please help!"
First of all, sit down, take a deep breath, and give yourself a few seconds to think about things before feeling like you have to come to any definitive conclusions.
The fact that you hooked-up with a girl after coming out as gay, doesn't actually change who you are. Sexual orientation is about a lot more than who we are being sexual with at one particular moment. Now it is true that you might be pansexual (which usually means that someone feels attraction to people regardless of their gender identities, sex or sexual orientation). But going to third base (usually manual sex / handjob or oral sex), can also just be something that happened despite your sexual orientation.
Keep this in mind, as well: plenty of people who identify as straight have had a sexual experience with someone of the same sex, either because they were curious, questioning, or just because it felt good. You are allowed to have this freedom to experiment, too!
A 16-year-old bisexual boy from Kansas offers this advice:
"You could be bisexual, but it could also be an exception. You could still be gay but be attracted to that person in particular."
Another teen, this one a 14-year-old who identifies as a gender-fluid lesbian says:
I think it's unfortunate that in our culture there's so much pressure to have a clear and constant idea of your sexual orientation, that we treat it as an either-or sort of thing, because it really is a spectrum, and where someone is on that spectrum can change over time, and that's fine. It can be comforting to have a clear idea of what you identify as, but if you love someone you shouldn't let that get in the way."
Ultimately, sexual orientation refers to the direction of a person's romantic and sexual attractions.
But as the teen above said, sexuality and sexual orientation can be fluid and can change over the course of someone's life. It is also common to feel as if you don't fit into any of the "typical" categories. And, as you know some people identify as pansexual. Others identify as asexual, stressing that they are not romantically or sexually attracted to other people, though they may still enjoy close and intimate relationships.
But many people choose not to define their sexual orientation using any of these terms. Though claiming an identity can feel comforting, and empowering, and give teens a sense of belonging, it can also feel limiting. There is no "rule" that says a 15-year-old boy has to pick one sexual orientation and stick to it forever. Plus, lots of people question their sexual orientation throughout their lives.
Lastly, since you previously came out as gay, it sounds like one of your concerns is what other people will now think. Really, there is nothing much you can do about that. It will probably be really irritating if people try to use the fact that you hooked-up with a girl as "proof" that you aren't truly gay, or suggest that this is a sign that you could change your sexual orientation if you really wanted to. But if you get honest questions about why someone who calls himself gay would also hook-up with a girl, you can honestly say, the experience surprised you and you are also trying to understand what it meant.