People are at their most fertile just after an m/c or giving birth. However, if a test is showing positive it may still be the hormones still present in your body
I know a few people who went to the doctor after a miscarriage because they "never had thier period" and they found out they were pregnant again already. So yes, you could be, if you think you are go to the doc. You are really fertile after a miscarriage (so they say), so you never know. One of the reasons they tell you to wait a cycle before TTC is so that when you take a test, they know it is because you are preggo again, not because you still have hormones in your system from the last pregnancy, but if your levels were monitored and were back down to below five, this should not be an issue.
do you mean could you get pregnant again right after the miscarriage or could there have been 2 babies to begin with?