My platy is pregnant and in a seperate tank She is stressed What should I do!?

Cover the tank so most of it is shaded. If you can find a styrofoam cup, cut a hole in it and weight it down with something so she has a place to hide. You can put a couple of dead oak leaves in the tank, too. It'll soften the water, give her a natural object to hide under, and she'll benefit from the natural tannins. Add a little bit of salt (aquarium salt is best but a pinch of iodized table salt won't kill her).