Progesterone levels

I am 4 weeks alone and had my progesterone levels taken on Monday.  They came back at 4.1.  The nurse indicated that was VERY low and that I was most likely having a chemical pregnancy.  The hgc levels were 52.  They retook my hgc levels on Wednesday and they came back at 101.  we are still proceeding with caution knowing the numbers are low.  Anyone else have this happen?!?!