some advice please

Well im 17 and my period was a couple days late(supposed to get it Thursday that just passed) and it came last night at 1:00 am and this morning when i went to change I wasn't bleeding anymore. Can somebody help me figure out this problem ? Also im sexually active but i use protection & the last time i had sex my bf's condom came off while he pulled out but the condom opening was half way out( he got a little bit on my legs but that's it)