I was told i was having a miscarriage a week ago my hcg levels went from 684 to 312 in two days but now they went back up to 762 could i be pregnant?

Concern: It's very concerning that your levels dropped and then went back up. You need to be followed closely. There could be a lab error, you could have an ectopic pregnancy, or there's even a cancer caused by pregnancy that could be a possibility. Bottom line you'll want to make sure Dr follows your levels. At around 2000, a small sack can be seen in the uterus if A viable pregnancy.