If you have a miscarriage can u get pregnant in the same month? like within a week?

Unlikely: Hcg, the hormone of pregnancy, prevents the ovary from releasing another egg during a pregnancy. Following a miscarriage, it takes time for the HCG level to decrease to normal non-pregnant levels (how long depends on how high the level was at the time of miscarriage). Another pregnancy cannot happen until the HCG is negative and the ovary releases another egg.

Yes: It's possible to ovulate by 2 weeks of an early miscarriage. You are probably noting a positive pregnancy test after a miscarriage, remember it takes time to have your HCG (pregnancy hormone) clear your system. If you're not experiencing more or increasing nausea, breast tenderness, or symptoms of pregnancy, you're probably ok. Check with your doc to make sure you completed your miscarriage & for f/u.