My pittbull had an upset stomach for 2 days. Now ...

Have her seen by  vet ASAP. She could have a blockage, could have ingested something toxic, maybe has food allergies, there are just too many variables to diagnose over the Internet.

Not eating at all is never a good sign, please call a vet and have her looked at.

Good luck !

Please take her to your vet immediately.  Don't take no for an answer, call vets until you can get her in and get her in by tomorrow morning,if not tonight.  Offer to wait in their lobby, The best thing at this point would be to be parked in front of their front door 15 minutes before they open tomorrow.  Early morning appointments are the ones that people most often miss or are at least late to, so be the first one at the veterinarians office, and you will likely get her seen.  I agree she could have a blockage or one of many issues.  When you say that she had an upset stomache for 2 days, what do you mean?  Since it must be something you are observing, was she just eating less, or did she vomit or have diarhea?  Have you changed her food or is there any chance she got into something poisonous?  This is a problem time for anti-freeze, since many of us are adding it to our cars water systems this time of year, getting ready for winter.  Anti-freeze attracts dogs by its sweet smell, but it is terribly toxic.  To anyone out there, it is well worth the couple of extra dollars to get the less poisonous types, it can save an animals life, if you spill or your car overheats or leaks water.  In the mean time, before you can get her into the vet, try giving her a very bland food.  Their is a canned science diet that is a rice blend, and you should be able to find it or something similiar at a large pet store like Petco or Pet Smart, etc.  Or try boiling some chicken or rabbit or lamb with a low roughage (not course) brown rice, don't fry the meat, as dogs can't digest grease.  Try giving her small amounts after it has cooled.  Make sure she is drinking water.  You should give her some of the water that the meat was boiled in, but be sure to skim off any grease, and toss the grease.  If she still won't drink, you will have to get water into her mouth by using a syringe (Without the needle) like what you would use to give a liquid medicine in your dog or child (an eye dropper is way too much work and the dog will tire of the game before she gets enough to do much good).  If you don't have an syringe, use a straw and put it in the broth and put your finger on top then put it in dogs mouth and remove your finger to release the liquid.  If you are having to do this, I would suggest doing it a few times ever hour all night until you can get her to the vet and get her on IV fluids.  It could very well make the difference in keeping her from getting dehydrated, which can kill her.  You can check for dehydration by taking some of the skin on the back of her neck between you finger and thumb, if the skin does not return to the back of the neck really fast, she is getting dehydrated.  Also, check her gums and tounge and see if the are pale.  When your dog is healthy you should always do these 2 things, that way you will have an idea what healthy looks and feels like, and you will have something to compare to when you have health concerns for your pet.  Good luck, and I hope she gets well soon.  

I agree with the other answers, she could have a blockage or couldve eaten something toxic. My golden retriever ate mouse poison and didnt eat for 3 days, vet gave her i.v she was fine in a week. I had a shepard mix who ate part of a tennis ball that lodged in his intestines, he wouldnt eat, we took him to vet, xrays ect. It thankfully passed next day!    You seriosly have to take her to vet IMMEDIATELY

You need to get her to the vet.  She might be bloating!

Okay...first of all...eww and poor doggie and cuatro, raokindness....who writes something that long...I'm sorry I luv animals really I'm just an upset tenn right now