HCG drop

Hi guys, I went to the hospital on Friday (15th june) and my HCG levels were 330~, I am about 4/5 weeks pregnant. Unfortunately on Sunday (17th) my HCG had dropped to 258~. Now my cramping has completely stopped, but I have no symptoms at all, yet I'm still getting positives. Is there any chance my HCG could rise again? Anyone else experienced this? I have had 3 miscarriages before, but I am trying to stay positive... Thanks for any help x