Help! BBT drop 15dpo after getting bfp at 11dpo

Stefanie

So I had BFP a few days ago at 11dpo and continued temping since then. My temps have been high but this morning plummeted about 0.4 degrees. FRER test is showing a dark line but I am panicking about the bbt drop. Does this mean I am going to MC? My boobs are still killing me, and I have been having intermittent light cramping for the past week. I also accidentally had some water before temping this morning but I don't know if that could explain such a big drop. Help! Anyone else have this?? Pics of temps, FRER 11 DPO (fl) and 15DPO.