I don’t know what to do.

I have gotten my period last month and had a weird cycle of a week of spotting and then a normal period after that. But now my period is ten days late I have taken a pregnancy test and had shown negative. I have stopped taking birth control and do not know if this is all just side effects. I’m thinking about going to the doctor within the next week to get checked out but I was wondering if anyone else had this happen or know anything about it.