If you did not use protection then you do not know if he got a little sperm inside you or not.Precum does have sperm in it.Yes having sex can make your period a little late.But since your on birth control then you should be fine.They have pregnancy test that you can take 4 days before your missed period.Or wait like a couple of days and take a regular test.You might want to get the digital pregancy test the ones that say NOT PREGNANT or PREGNANT,because sometimes the regular ones are a little hard to tell.

If you take you bc everyday like you are supposed to I'm sure you are fine. That's what the bc is for Maybe just give it a little longer and if you still havn't had your period take another test. But like I said I'm sure you are just fine!! Don't stress it makes it worse!

this really helped calm me down. i got my period the next day

I ALSO want to add that your period can come ANY TIME during the inactive week, MOST women do not have it start the first day.