My periods a day late and usually lands on the 28th day me and my boyfriend use condoms all the time but 1 time the condom slipped inside of me when he ejaculated. iwasnt allowed plan b pills im 17?

Well, I will say that it is very wise for you to be on birth control and he using a condom at the same time. And yes, the condom slipping does happen unfortunately! But I wouldn't be too concerned. Sometimes Birth Control pills can really mess with your periods. If you are too concerned you should just take a home pregnancy test. Good luck!