Worried

So this will be a kinda long post but i would love advice / thoughts on what is going on. My last period was on Sep 9th went as usual four days mild cramping you know the average period. On the 20 i had sex with my husband. I started bleeding/spotting the next day(21st). My ovulation should have been the 23rd and based on signs it was. I have continued to have pink spotting daily and very rarely red spotting and also very rarely cramps. On Fri the 4th i got a postive pregnancy test. On Monday i got my first hcg it was only 221. The Dr had another done Wed it was 238 so went up but didnt even come close to doubling. They have asked me to come in for another tomorrow. My period was due on monday the 7th and it didn't start just the same spotting/bleeding. I am so scared i am having a miscarriage.