My progesterone level dropped?!?

i found our i was pregnant at 3 weeks. ( i ovulated late so i thought i would be at 4 weeks). i bled a little bit the night and day after i got my positive tests. doc said if bloodwork did come back as pregnant she was sure what i was having was a miscarriage. the results did come back as pregnant. hcg and progesterone were a bit low but both in normal range. so they said they just need more blood work to make sure my levels return to zero before we start fertility treatments. so i did more bloodwork and it came back that my hcg doubled just like it was supposed to! it wasnt a miscarriage. but then the nurse said my progesterone had dropped a bit....and the doctor would call and talk to me about it when she got out of surgery. but she never did. and now it is the weekend! so i am all freaked out. does a drop in progesterone mean miscarriage even if hcg is good? and i am so confused bc if my progesterone levels were low and needed to be on supplements like they say on here, wouldnt that be a time sensitive thing? ughhh. im so frustrated....please help if you can. thank you