I noticed today that my 12 year old cat named Gracie was lying on my bed in a strange position. Her butt was up in the air and her tail is curled over at the base of her tail, almost like female cats stand when they are in heat but lower. I pet her and she strange noise. When she jumps down from something she walks with her hind end lower. She doesn't want me to touch her or pick her up. I did see her drink water and eat a little but other than that she doesn't want to move. I am really concerned. What could this be?