Hi!
It is difficult to say whether or not this is a new pregnancy, but I rather suspect that it is! The way to find out is to have quantitative beta HCG levels done 48 hours apart and compare the two. If it is a new pregnancy, the level should approximately double. If it is left over from the previous pregnancy the level will probably fall.
If you are pregnant again, there is no need to worry about anything other than the usual worries. If you're not pregnant again, you haven't done any permanent harm, but it would be a good idea to wait until all the pregnancy hormone clears your system so that you can start fresh.
By the way, I always like to look at the positive side of the miscarriage--you now know that you CAN get pregnant! If it can happen once, it can happen again. Maybe it already has!
Good luck!
Dr B