8 days late and guess what! BFN

My period has always been one or two days late, I'm not sure when o'd, just using the app  to tell me. I just bought a bbt therm for next month incase this month is not the month. I have no period symptoms at all. Strange cramping not the usual pms ones. Totally confused! I just keep having to click "my period is late" on the calendar. Cervix is still high. I thought I had a faint line on one buuut the next one I took Bfn. Ugh. Come on AF just show your dumb head.