I'm mad at a pregnant coworker.
What all happened with you two?
She used to be fine until she got pregnant.
Relationships with coworkers can be difficult to manage, but you shouldn't be mad at them for getting pregnant. Going through pregnancy is very difficult for people, so you should try to be more patient with her. Getting mad will just make both of you feel worse and not solve anything.
I'm going to make her feel bad by calling her fat and telling her how unhealthy she's being.
It is wrong to cause problems and stress for pregnant women. If you have issues with her you should talk to her alone and try to find an understanding.