Low hcg?

So my period was due April 3rd I decided to take a pregnancy test at 2 days late and I had two faint lines. The next day still no period so I took a digital and it said pregnant ! I was so happy because I just lost my last baby March 12 so this is my rainbow baby !! I had blood work yesterday and my doctor called and said your pregnant ! He told me to come in today which I did. He told me my hcg was at 34 and yesterday I was only 4 weeks 3 days he told me I was going to miscarry and walked away. He had his assistant hand me a paper for another blood work for Thursday. Also I had to take a pregnancy test there and they Told me it was negative but when I looked at it the line was there and wasn't as faint as the first time. So I called them back and asked them how is it that the test is showing two lines and you guys just told me it was negative and im going to miscarry when I don't have any pain and I'm perfectly fine. Had anyone had an hcg this low i know it's early but he told me I expect it to be at a 0 by Friday SMH thanks doctor.