Temp rise or drop when period was due?

Glow said I should of started my period yesterday. I keep having mild cramps as if AF is going to show but doesn't, temp is at 98.45 today highest it's been all month. I've tested a few days before my period, all BFN's so I'm waiting a few more days for AF but y question is did your temp rise or drop when AF was due for you or a couple days after missed period?