*update* Help! can anyone tell me what's going on?

can someone help me understand what's going on with my chart. We had a loss and a D&C; end of August and we've been actively trying since early November (when I got cleared by my doctor). In my previous charting I never had a significant drop in bbt like I did this cycle. my cycles have been irregular so I went to the doctor and they did an ultrasound and everything looked normal and my doc said it looks like I was ovulating like my chart says (I've been having a hard time figure out when I'm ovulating. AF is due in 6 days. I've had mild cramping and my nipples have been sore. Any help would be much appreciated.

*update* Then this happened this morning. Have a feeling AF is about to show up 😭😢😭😢

update again- ok guys....what is my body doing?!?! today it jumped back up to 98.20. has anyone had this happen when charting?