Makes no sense to me and I’m so confused

My app says 11 days late. It’s 28 March and I am not started my period yet this month. I had horrible cramps a few weeks back Like I was on my period but there was no blood to it It was more brown and gooey stuff coming out of me But it was only like 2 days with the brown and gooey stuff coming out of me. I am on BC I have been on birth control for pretty much 3yrs now. I take it every night there are times where I will forget one pill at night but I will take That Miss pill along with the next nights pill. I did have sex with my boyfriend And he did claim that he came with me twice. I didn’t miss any pills before we had sex. I did take a pregnancy test a week after we had sex and the next week after that week I took another so I did take two pregnancy test within the two weeks after having sex but both test came back negative. I’m not having any pregnancy symptoms. The only symptoms I am having is just allergies lol. I’m a little concerned. Should I take a third test to be safe or does it sound like my birth control pills could be stopping my period????????