Struggling with my Parents

I am just over 4 weeks pregnant, and the only people who know are me, my SO, and his mom. His mom was incredibly supportive of us and even somewhat excited despite the fact we are quite young and this was not a part of the plan. My family on the other hand, do not know, and quite possibly will cut me off completely when they find out. I'm just really struggling with that and it is making it where I don't even want to tell them about it, and thus I have all this negative energy surrounding my pregnancy. My SO has a hard time understanding because his family is not at all the way mine are. My family will be disappointed to have me associated with them, and its sort of tearing me apart. Has anyone else dealt with this? And if so, how did you get through it?