As long as your not an at will state they can't fire you and most big companies have a 3 strike rule check into that I'm sure you'll be fine :)
I let them know since I've been so affected by the pregnancy. I'm just worried because I know my performance is being affected as well.
They can't fire you for being pregnant. If they don't know already then let them know you are expecting.
Does your job know your pregnant?