I'm thinking of my best friend might be pregnant and I don't wanna speak to her anymore
You should be nice to someone if they are pregnant right?
She didn't tell me about her pregnancy.
Pregnancy is a private matter and it's not something that is easy to tell others about. You are being pretty rough and heartless if you plan to abandon her over not telling you about her pregnancy. Even as friends you need to respect privacy and boundaries or other people will think you a horrible person.
No, I don't care what others think about me.
Just because someone has gotten pregnant should not mean that you do not want to be friends with them. I would assume that this is really hurtful to your friend.