Hcg levels

Hello, I was spotting off/on for about a 2wks. Doctor ofcourse said its normal in early pregnancy. But Monday it was brighter red. I was concerned cause I had a MC in May & sarted w/ "normal" spotting as well. So I asked to have my HCG levels tested they were 12,731, according to last menstrual cycle I am 7 wks today. I go back Friday for another test to see if levels are getting higher or lower. Is that on the lower side of where levels should be? Has anyone had them on the low side & still had a healthy pregnancy?