BBT slow declining.... miscarriage?

Stephanie
Help! In a panic. I've continued tracking my BBT and currently I'm 5W1D pregnant. I peaked a few days at 98.55 and over the last 4 days it's steadily declined down to 98.29. My cover line is still a bit away at 97.3 but I'm concerned that I have a declining progesterone level which could cause a miscarriage? I read an article that the Dr may be able to give me a hormone treatment to bring it back up in cases like this. Thoughts? Has this happened to anybody with a successful pregnancy???