Could I have gotten an STD...?

There is always a chance of getting an std with having sex. But I would say, in this situation, probably not. Condoms are only like 98% assuring of not getting stuff like that (health class?) Anyway, because you were using a condom, I don't think you would have gotten one. If the woman you slept with had an std, that would probably increase the chance of you getting one.