advice?

So a little backstory..

after having a miscarriage in november , i became pregnant again in march and everything seemed to be going well. my hcg levels were rising BUT i was advised to be put on progesterone by my previous dr. well , i started seeing a new ob and he refused to put me on bc i was “too young” and due to my previous loss i “probably wouldn’t be pregnant for long”, now my levels have dropped and i am scared i am going to miscarry again all bc he refused to put me on progesterone. are there any success stories of hcg levels dropping and then rising again? i read that although it isn’t common , it does happen and my levels didn’t drop by more than 100.