Another miscarriage? Low HCG rising slowly

I’m thinking this will be another miscarriage 😢I got my HCG levels back and they are increasing too slowly... 72 on Friday to only 145 on Tuesday. Has anyone had a slow rising HCG turn out ok? Or should I just be ready to miscarry any day now? I had a miscarriage at 5 weeks already just at the end of April, no cycle in between, now this... because the levels are so low any guesses as to why this might be happening? I asked my dr to test progesterone but he didn’t think it was necessary because I had only miscarried once, I really wish he had now 😢😢😢