You don't necessarily need to have other symptoms. Every person and every infection is different. I have been getting recurrent UTI's for 8 years. Sometimes there will be blood in the urine, other times it will just smell really strong like ammonia. While a lot of people get fevers and abdominal cramps with UTI's, I have never experienced either of these. The only way to diagnose it is to go to your doctor and get a urinalysis. UTI's can become very serious if they spread to your kidneys and have the potential to cause permanent kidney damage, so it is very important to get them treated asap.