being sick and the pill

So I've been sick the past few days. I've had cold/flu like symptoms but it could also be really bad allergies. I've been taking a lot of medicines for those symptoms and today me and my bf had unprotected sex and he finished inside me. I've been on birth control for about 3 months now. Do cold/allergy medications affect the effectiveness of the birth control pill??? I need help idk if I should get the plan b pill