It sounds like you have a sick dog and one that is probably in pain. There would be no way to be able to tell you what is wrong as it could be any number of things. It us very worrisome that she is shaking, not eating or drinking. You need to find some way to get her to the Vet and soon! Some take Care Credit. She needs to get checked!
Money or not, get to the vet. Tail tucked, walking funny, pain all over, distended belly are all signs of a medical emergency. Call a few vets, explain your situation, and see who seems the most open to help. Also, ask your friends on Facebook to chip in and help. They can callthe vet's office and pay $10 or $20 towards the bill.
I agree with both comments above. Your poor dog needs some medical help. She is obviously feeling rotten, and no-one here can diagnose what might be the matter with her. I can tell you love her so do something to get her to the vet.
You need to get your dog to a vet whatever the cost. Shaking is an indication of pain, and if she won't get up when you call her the pain is severe enough to make her not want to move. The hard belly could be a mass, it could be caused by a blockage, only a vet can tell you. She is, apparently, suffering, so you need to just get out your phone book and start calling vets, explaining the situation and begging them to please see her with your promise (that you absolutely keep) to either make payments or pay when you get the money. You can also apply for Care Credit. You will find out immediately if you are approved and it's likely that you will be approved. In my experience your credit has to be really bottomed out to be turned down. Please don't let her go the whole weekend like this.