QuestionMy cat is about 14 weeks old, and around 4 pounds. I weigh about 130 pounds.
AnswerHmm.. It would be difficult to diagnose without seeing your cat in person! Does she drag her tail at all?
You could call a vet and ask, or if she is exhibiting any odd behavior like lethargy or her tail seems limp, you could take her in for a examination.
Also keep in mind, tails are very flexible, and if you just sat directly down on it, on a soft couch or bed, i doubt it would hurt at all. If you stepped on it, though, you probably have reason to be concerned.