Poor Layla is not feeling very well

We stayed over at my grandma's house on Saturday night, and she was her normal self. She slept soundly all night and ate her breakfast in the morning. Later in the afternoon she went to look in her empty food bowl, but we were leaving for home soon anyway so we were just going to feed her there. When we got home we gave her some food but she wouldn't eat it. We left it out all night and she didn't eat. I woke up to her crying at 3:30 am. I went down to see if she had pooped or something (usually that's the only reason she cries!) but there was nothing there. I comforted her and tried to go back to sleep. She wouldn't stop crying. I thought maybe she's finally hungry! So I went downstairs to get her food and brought it up but she wanted nothing to do with it. I put it in her mouth and she spit it out! She seemed to want to jump into my lap so I brought her onto the bed to cuddle. She was restless. I started getting really worried that maybe her back was hurting again

Her stomach was very tight and it kept growling.
She cried for the rest of the night but I managed to get a little bit of sleep. Scott took her in for rehab this morning and mentioned it to the vet. She didn't eat her breakfast this morning either. The vet called this morning and said they will not do rehab on her today. She checked her over and she seems to have gas but everything else seems normal from a quick examination. If I wanted, they would do blood work and x-rays but I said let's wait and see if she's better tonight. If not, I can take her back tomorrow. They are going to try feeding her some different food and send some home with her when we pick her up later too. I am worried about another problem with her back. Now that her back legs aren't working we won't have the major warning signs. It is just very weird for her to be crying at night like that.