pregnant while on Birth control?

alright so I had sex with a condom about a week ago and we couldn't tell if it was broken or if the stuff was from me. I am also on birth control. my Period should be starting sometime this week. my discharge is very watery. and since I've went to eat at my S/O grandma's house I've felt sick. could that be a coincidence, or could I be pregnant or am I just over reacting?