not wanting my child to see his family....

I'm just curious as to how you would go about this....
After telling my SO's family I was pregnant they quickly DEMANDED I get an abortion, which I did not go through with. Then as I got to 12 weeks they told me I lied and said I was only a month pregnant a few days before that....(I never said that I had told them 100 times I was almost 3 months) anyway now I am 28 going on 29 weeks they are acting excited and throwing me a baby shower....less than 5 months ago they wanted me to get an abortion....am I overreacting by saying I'd rather they not be around my son? They didn't want him then...why now?
Update: his mother has also wished disabilities on her grandson and said she wants no part in his life at all and would not accept or support this pregnancy. She also has my SO freaked out that his son won't have all his limbs or won't be fully formed because I forget to take my prenatal pill once in a while and don't eat 10 times a day...