Am I pregnant?

I’m currently not on birth control and for some reason each month, my period gets later and later. For example my period would always be two or three days late and the next month it would be two or three days after that. Well this month, my period has been really late. When it got to seven days late I took a test and it was negative. It’s been sixteen days and I still don’t have it. Should I take another test? Or should I just wait for my period?