Food or pregnant?

I'm still not 100% sure if my new shelter cat is pregnant. She looks like it!
I have her and my other cat on purina one indoor formula. I switched to that since my other cat use to have hair balls and throw nasty crap up. Now he's doing great!

Shelter cat has been throwing her food up but it's still in normal cat food form lol chewed up bits of it. I know she has to get use to it since at the shelter it's a whatever they have feed. She's been with me for a week now.

Should I look into new good again? (Asking now since I'm about to go to the store for more cat food) or give it some more time? Or could this be a pregnant thing?

Change to another food, preferably go to wet food until her tummy is settled again.  Then try getting her some grain free food (they even have that at supermarkets now) with no wheat, corn or soy.  Shelters feed what they can, but some cats are allergic to it and can have problems.  Try to find what works for her rather than try to force her to get used to food that doesn't agree with her.  Publix has their own brand of grain free dry food now that isn't too expensive, and it has agreed with my rescue cats with no problems so far.

Do they have Publix in Westet Virginia (they do in GA and FL)

Not around here we don't. She hasn't thrown up for two days now. And my goodness she eats a lot!!!