On Friday, my cat was not holding her tail up. It felt swollen at the base and she appeared to uncomfortable, but continued to eat/use bathroom. She was very clingy all weekend. Come Monday, she began holding her tail up again and returned to her usual self, romping through the house and playing. She now has a hard knot on the bottom side of her tail at the base. Any ideas on what happened. I would have taken her to the vet on Monday, but now she appears fine. I am not sure what to do.