Hi I'm 14 Weeks Pregnant. Recently I Have Done Some

Hi I'm 14 weeks pregnant. Recently i have done some tests but to be honest result and visit to my doctor left me more confused then ever. The issue is that my blood type is O rh negative of course that was before pregnancy. The last test show that I'm O rh positive. So my questions is what is happening and is that dangerous for the baby? Next week i will make blood type test again to be sure. Also THS4 was a little high over 200 does it matter for the healthy develop of the baby.