I am 12 days late with negative pregnancy tests, should I go to the doctor or just wait on my period?

I took two tests when I was 11 days late and they were both negative, so I know there's no way I'm pregnant. But I'm starting to worry. I am on average a 31 day cycle and I am currently on a 43 day cycle. Should I just wait for my period to come, or go to the doctor?