Serious question

We had a miscarriage 4 almost 5 weeks ago. But I've started to have sore breast again, headaches, and nausea. Which happened both of the other times I was pregnant. Is it possible to get pregnant that early after a miscarriage? I've read that you're extremely fertile after a miscarriage and about some women who were 2 weeks pregnant after being 4 weeks out from a miscarriage. Could I actually have already gotten pregnant again? Or is that not even possible?