Help....I'm worried

Okay so I'm new to withdrawal and so is my bf of 4 years. But he has been great at not finishing in me. We've only used this method of birth control 3 times and I am not on the pill. I am going to start taking birth control pills again once my period comes... I'm worried because I feel like I could be pregnant because of the pre cum...BUT I also feel like I'm fine. I have not had any symptoms really just mentally being worried. I am supposed to get my period a week from now so I hope I will. I just want to know if anyone has felt this way and maybe give some advice..?