literally about to puke

This month I had sex maybe 4-5 times. I am on the pill and take it RELIGIOUSLY. He pulled out every single time, no cum got in me at all I am sure of it. I am due for my period in 4 days, and I am having brown discharge. I wasn't concerned at all about being pregnant until this happened because I've heard this can be implantation bleeding. I'm literally freaking out, i feel like now I'm having all the symptoms in the book. My partner told me he isn't worried at all and would bet his college tuition that he didn't get even one sperm in me. Please help??? Anyone else have this happen on the pill???