Low HCG levels

Hi I'm about 4-5 weeks along. I just found out I was pregnant last wed (1/9) and did blood test, HCG levels were only at 10mIU/ml. Today (7/9), I repeated the blood test as I had spotting and blood test results was only 31mIU/ml. Gynae has put me on duphaston and given me a progesterone booster shot and ordered for 2 days more of bed rest then retake blood test. Anyone had any experience with this? How did it turn out? I'm quite worried and praying really hard #firstbaby #pleasehelp #1stimemom #advicepls #pregnancy