Missed period, negative tests?

I don’t really understand what’s going on with my cycle this month? I have very normal periods, never more than a day off. I have an 8 month old daughter and I have been feeling slightly off almost as if I was pregnant. I’ve taken 2 tests and both negative! They are dollar store tests.. I’m not under any more stress than usual.

Should I go ahead and call my doctor or wait a week and test again ?