As well as temperature, check the mucus membranes for colour.
Tooth grinding can be pain, stress, toothache, rough teeth...
Are there any lumps and bumps or sore spots along the jaw, side of the mouth? If she's very tame she'll probably let you see inside her mouth to check she hasn't got a rough or sticky-out bit on a tooth somewhere.
Are her eyes bright and shiny?
Could she have ingested something inappropriate? Knickers off the line, baler twine, a lucozade bottle, a downed firework... ?
Burps and rumbles are encouraging... when you watch her left side, can you see the regular contractions as the rumen contracts in a wave from back to front? Should occur every 30 seconds. You should be able to see and feel it; I find the best spot to watch is the upper flank behind the ribs in front of the hips; the wave starts here and moves forwards.
A drench of natural yoghurt and sunflower oil will do no harm if you can't get out to get some pro-rumen. Add a little ginger if you have some. You should absolutely see and hear the rumen working after this.