serious question...

Okay so when I was about 10 weeks I went to my doctors appointment & they needed to take some blood. when I went back to my 13 week appointment they told me I had 0- blood. And my boyfriend has AB+. And my nurse told me I had to get the Rograhm(spelling) shot @28 weeks, and than another one after birth if the baby doesn't have my blood type. But I heard that my blood gets to the baby some how. So I'm just really confused on that. And also when they took the blood @ 10 weeks were they able to tell if the baby had any type of chromosome disorder or any sorta problems?