Sounds like a UTI. My daughter has had 8 since Jan 2007 and never shows a fever. Just irritability, back pain, and smelly, cloudy urine. I would take her to the ER and have her tested and not wait till Monday for your Doctor. Since your daughter has never had a catheter (mine is cath'd 4 times a day) it may bother her. Yes, it may hurt her (but thats because of the infection). Have them use the smallest catheter they can. Probably a 5 french size.
UTI's are not something to mess around with. If it spreads up into her bladder you are talking hospitalization and could lead to kidney damage. I'm not trying to scare you. But when you are talking about a baby that can't communicate exactly whats going on down there, you need to take the lead. With an older child/adult you can catch it sooner and correct it with cranberry juice/extra water.