just need clarification

okay, so I started birth control almost two months ago. I had unprotected sex (which was dumb i know) maybe about 2 or 3 weels ago with my current lover and he pulled out of course but as a girl, i always freak out with stuff like this. so i feel perfectly fine. but i've started to spot a little and having menstrual cramps along with it. i have been told it is because my period is being regulated and it is normal to spot while on birth control and what not and idk what to believe or anything! i just need clarification! thanks ladies! ❤️