My cat’s tail is hurt!

I have a six-and-a-half-year-old female cat. When I got home today, I noticed her tail was looking a bit strange. She can lift it about halfway, but the rest of it, especially the tip, is just hanging limp and she can’t seem to move it at all. When I touched her tail, she cried out and hissed at me. She even snapped at my dog, and they usually get on really well together.

What should I do?

Will she definitely need an amputation?

Please help me, I’m worried sick!!