I'll try to make this short and sweet.
I'm 17, and on birth control. I finished my pack, and was taking the green pills so that I could get my period. After my period had passed, we couldn't afford to pay for a new pack until 4 days later. So I didn't take the birth control for 4 days. During that 4 days, my boyfriend and I had unprotected sex, and he pulled out. I started taking my birth control last Wednesday, and it's Monday. I've been feeling really weird since we had sex, but I think it may be my anxiety because of the situation. I know for a fact that you can't get pregnancy symptoms days after having sex, but I just got a little worried.
Is it true that right after your period that's your least fertile time?
Is there any way I can know for sure that I'm not pregnant so I can put my anxiety at bay?