late again?

Okay so last month my period was 5 days late followed by my typical 6 day period, and this month I am 10 days late with nothing. pregnancy tests last month were negative of course, and this month I have taken one and it was negative. according to glow I am 21 dpo but I haven't been testing as we are not actively trying. I don't have any cramps, spotting, mood changes etc just slight bloating. is it typical for my period to be late like this all of a sudden? I've always been regular. I just don't know if it's worth a trip to the doctor or if this is normal..