8 days late

So my period has been coming late but normally only by 4 days, well today I'm 8 days late and still nothing. I took a test at 5 days late and it came back negative so I'm at a loss. We had a tubal pregnancy in July and have been ttc again since October. Last time I got pregnant it didnt show up until I was 13 days late but that's because I took it at 5 days late and then waiting another week to see if AF would show up. I'm getting a little nervous and just want my period to start, I've tried what I normally do to get it going but nothing is working. What should I do? Should I just wait for AF or continue to test? Thanks