miscarriage confusion?

Dec 7th 2014 had miscarrage natural and was 12wks pregnant Jan 21 had period Feb 18 AF was due didn't come feb 26th 2015 took hpt and positive so excited.. March 9 2015 went to the er with spotting when got to hospital I was 6wks 5days pregnant so I started bleeding at the hospital mildly and had few clots... Did HCG level 41,000 doctor said normal for where i was left hospital with threatened miscarriage papers and diagnosed me with inevitable miscarriage. March 11th do another HCG level went down a lot to 8300 I thought ok I'm definitely miscarrying I was still bleeding mildly One week after I had another HCG level done was 6,000 and bleeding completely stopped no cramping nothing March 19 2015 I go into different hospital cause I still felt completely pregnant I just wasn't convinced so they do another HCG level and it was 5200 so dropped 800 in 24hrs.. They did pelvic and said cervix closed no bleeding and they did ultrasound so when I left the hospital the ultrasound wasn't back but they said that I had UTI and gave me scrip for it... And said that they suspect I had miscarriage because levels are dropping and that there may be small tiny amount of tissue it will pass on my next period... So I left Week after hospital visit just this pass Wed did another HCG level Thursday Obgyn calls my levels at 5500 but they don't worry they are increasing cause another lab did this level test smh... So I go into today which is march 27 and they did another pelvic cervix still closed and no blood so the doctor says I got your ultrasound back and there seems like there is either small amount of tissue or blood in your uterus its to small to tell... We can do D&C to clean it out they wanted to schedule me next week I'm so confused has anyone gone through something similar or can give me any insight... Should I just do the procedure or get 2nd opinion I mean it will have been month on Monday since my miscarriage and I still feel completely pregnant and levels are still 5000s and I also gained 5lbs in the last 3 weeks... Monday which is one day away it will be month since my miscarriage and I still feel and look pregnant... Not to mention I gained 5lbs in 3weeks