Newly pregnant, hcg numbers

I found out on the 4th we are pregnant again, 4 weeks. Had blood work done on the 6th - HCC in the low 200. Had blood work yesterday and number is 342. I've already had a miscarriage and a very high risk/ stress pregnancy which gave resulted in our beautiful rainbow baby. I'm afraid I'm going to have another miscarriage.

Current Symptoms: (which I've never had in my previous pregnancies) headache, bad lower back pains, nauseous, indigestion/ stomach cramping and period cramping pain.

Anyone have similar experience? I'm trying not to stress but I can't help it!!