Should I take my cat to the vet???

Yesterday my outdoor cat Cali was outside and she came back and I was petting her and I noticed blood on her tail not a lot just enough to come off on my hand I cleaned her tail and everything and she seemed fine. She's been playing eating drinking water acting how she always does. Today though my sister Accidently stood on her tail and she cried as they always do but now it's got a wierd bend in it? She's still playing eating and drinking I'm just really worried its broken. Should I take her to the vet or is it just sore from being stepped on?

Since she's got a "weird bend" in her tail, she should be seen by a vet ASAP.

Agree with JCat, especially if your cat's balance seems off (cats use their tail for balancing).  One thing to keep in mind always:  cats hide pain to the nth degree.  So even if your cat doesn't act like he is pain, he may very well be.

I always prefer to err on the side of caution.  If there's any concern whatsoever, I at least call the vet and sometimes end up taking my kitty in.
 

Either I missed something or you did not indicate where the blood was coming from ie: wound etc.  The bend in the tail is a definite reason to see the vet, if nothing else.  I've learned that when I ask myself if I should take one of the animals to the vet - I immediately pick up the phone and make the appointment.  If I have to ask myself that question, I don't have a clue what is wrong and need to find out.  I'd get her to the vet if it were me.