UTIs are common infections that occur when bacteria enter the urinary tract through the urethra and begin to spread into the bladder. Common symptoms include: pain or a burning sensation when you urinate, a strong urge to urinate that doesn’t go away even after you’ve emptied your bladder, frequent urination where you can only pass small amounts of urine, cloudy, bloody, or bright pink urine, strong smelling urine, pelvic pain, pressure in your lower back or pelvis, and some UTIs may cause mental confusion or a temporary state of delirium.