It sounds like you are very worried.
Your first course of action is to confirm that you are indeed pregnant. Once that has been established, you can make plans. It is no use panicking and making yourself sick with worry about something that has not been confirmed yet.
Kicking a child in need out is not how normal parents react. They can be disappointed and angry, that is normal. They might say one thing now, but when reality hits, they might react differently. Talk is easy. When you become a mom, they become grandparents. So they have a responsibility as well.
Why are you taking chances like this when you know their position on it?. There are enough ways to have all the fun you want an still be safe.