My period came earlier than usual and lasted shorter, we used condoms every time

Could I be pregnant? My bf and I had sex for the 1st time. (We are both adults) I always been using condoms since the 1st time I had sex.

3 weeks ago, we had sex...I saw him taking the condom out of the wrapper and he put it on. We started doing it. He later took it off....few mins later, he opened a new one and we had sex again.

3 or 4 days later, my period came (it wasn't supposed to come until 1 week later), it lasted like 3 days, its usually 3 to 6 days. What does that mean?

Since its been 3 weeks since I had sex, I feel like I want to vomit, but not so bad...although I did ate something bad. I am not peeing a lot, my breasts feels fine. I am just a little nervous.