XP: Blood clot in dog's urine - what is this??

I also posted this over in Health:
 
Please help!  My husband & I were about to go to bed when we noticed that Lola had piddled on the carpet.  She has not done had one single accident since she had her UTI about a month & a half ago - cleared up w/medication.  She has been so great at only going potty outside and she always tells us if she needs to go out.  Anyhow, tonight when I bent down to clean it up I noticed a small blood clot about the size of a dime, in the middle of the puddle.  About a foot away was another little drip of blood.  Her urine also had a very strong odor.  I am assuming that this may be another UTI, but am worried that it could be something worse.  She seems fine otherwise - as usual, she is constantly whining to go outside [&:]  I am going to get her to the vet tomorrow.  Until then, I am worried...