A lower urinary tract infection (affecting the bladder) typically causes a burning sensation when passing urine, a frequent and urgent need to go, passing only small amounts, cloudy or unusually strong-smelling urine, and sometimes blood in the urine or aching in the lower abdomen. These infections are very common in women because of anatomy.
Symptoms that suggest the infection has spread to the kidneys are more serious and include fever, chills, back or side (flank) pain, nausea, and feeling generally very unwell. These need prompt medical attention.
Seek urgent care if you have fever, back pain, vomiting, confusion (especially in older adults), blood in the urine, are pregnant, or if symptoms are severe or worsening. Mild bladder symptoms can sometimes settle, but if they persist beyond a day or two, see a clinician, as a urine test and treatment may be needed.