Can anyone please help me.

I am having an awful time. Let me start from the beginning and I apologize in advance for the length. 
Four and a half years ago, I was diagnosed with ovarian cancer. I found out because I was taking positive pregnancy tests. My hcg levels were fluctuating and my progesterone was 0. 
March 13, I took a positive pregnancy test. Here is how my hcg and progesterone break down over my next few blood draws. 
March 14th- hcg was 49 and progesterone was 18
March 17th- hcg was 175 and progesterone was 24
March 19th- hcg dropped to 155 and progesterone stayed at 24. 
At this point I was told that I was having a miscarriage. I experienced awful back pain and nausea from March19th until March 22nd. My doctor then sent me for more blood work to make sure everything was dropping okay. 
March 24th- hcg rose to in the 400's but progesterone fell to 7. 
My doctor actually told me that they're not sure what is happening. Hcg doesn't just drop and then rise again. They are having me go in on March 26gh for more bloodwork and an ultrasound. The said it could be a relapse of my Cancer (but since I have progesterone they are not thinking this.) it could be an eptopic, or it could be a healthy pregnancy with an unexplained drop. I have had no bleeding. 
Can anyone please tell me this happened to them and they had a healthy pregnancy. I'm so lost.