yess it is v.serious problem.. if not treated timely u can have septicemia, pyelonephritis and other complications needing hospital even i.c.u. admission.
Next Steps
first give urine sample for culture and sensitivity immediately and start some antibiotic and urine alkalizer after consulting physician / gynaecologist.then antibiotics will be changed according to culture sensitivity report.
till then drink 4-5 lit of water .. do frequent urination.