6th pregnancy

After having 4 miscarriages, I was diagnosed with MTHFR.  I began taking lovonox shots in my stomach with my 5th pregnancy but still miscarried.  With this pregnancy, I am currently 6 weeks, I have been taking the lovonox shots, along with progesterone suppositories, vitimans, and folic acid suppliments.  My first hcg level was 1119, 3 days later, my hcg level was 4244.  I don't believe my hcg levels ever got that high, but of course I am still very worried about miscarriage.  Do hcg levels help determine viable pregnancies? Should I feel better that my hcg levels are going up at a reasonable rate?