birth control pregnancy

i have been on the shot for almost a year now, last month i started the pills. so i am currently on the pill and the shot. the thought of having a baby scares me. but i have been so nauseous lately, i went to my doctor and he just said “oh you’re fine we’re justing going to give you some antibiotics” and that wasn’t very reassuring. cant antibiotics cant out birth control? and why do i keep vomiting 😣