Positive HPT but BBT dropped!

Di

This is my first pregnancy since my miscarriage in March. My husband and I are both happy yet scared that it will happen again. Sure enough, I woke up this morning to a dip in my BBT. No spotting yet though, just mild cramping. I'm praying it's not a chemical pregnancy. Please help me figure it out! I'll be calling my doctor tomorrow. Ugh! I should be SO happy right now to get a pos HPT, it just goes to show that you can't get too excited when this happens.

HPT's yesterday morning at 8am then today at 8am.

My temp dropped. Although not below the cover line yet, I know that the temp needs to continually increase past 18 DPO. What do you think?