pregnant?

Sooooo I had my son August 23 when I was 4 weeks pp I had sex using the pull out method and we did that a few times then after that we used condoms also a few times this past weekend we had sex didn't wear a condom and he came in me... I haven't gotten BC becuase I go this week coming up... I exclusively breastfeed...
When I go to the doctor do you think I should wait to get BC just in case I can be pregnant ?what do you recommend? of course I'm going to tell my doctor I had unprotected sex..