BBT drop and got a BFP! Am I miscarrying?

Have you done anything else the last few nights, like get up to pee, sleeping with a fan on etc? These can all cause erratic temps. If not then please see your doctor as this could (and I mean could, not "is") be a sign that progesterone is dropping and the pregnancy may be lost. But I've seen loads of charts like that that result in perfectly healthy pregnancies! I still think a trip to the doctor is a good idea though and ask for a progesterone tet, hCG test and progesterone suppositories.