5 weeks, some brown spotting cramping

Help! Terrified I'm beginning to miscarry. I'm 5 weeks and was having some cramping last night with brown spotting only when I wiped. I called the doc and they ordered more blood work and said my progesterone is 1% lower than they like to see (14.02) and they want it over 15. All other blood work was normal. Spotting has stopped and cramping is much less. Anyone else have this happen? I need advice please and thank you!