Scared Now

Roux came in last night about 11:30.  She was dragging and once I actually saw her, she was shaking like a leaf.  She is covered in little scratches and her skin is red.  I got her fed and on the couch, and she continued to shake.  She slept immediately and hard.  This morning, she's still shaking slightly.  I'm going to take her to the vet, but I'm so scared she's eaten or been given something toxic.  I keep thinking about Rufus, the neighbor's Rottie who died.  I can't stand it.