I had a surgical termination 6 wks ago, but my bhcg result is 348. could it be declining still, or am i more likely pregnant?

Hard to say: It does the some time for hormone levels to return to normal, however if you have been having unprotected sex since that time there is no way to tell if this is 1) left over hormone from the last pregnancy, 2) a new pregnancy or 3) tissue that was accidentally left behind during the termination that is still making hormone. You should be followed weekly by your doctor to assess this