The brownish color urine results from either very concentrated urine or blood in the urine.
Sounds like you may have a urinary tract infection (most likely in that left kidney) and it will need to be treated by your physician with antibiotics. In the meantime, drink plenty of fluids to keep your urinary tract flushed. Cranberry juice is a good drink for your kidneys, too. Be sure to call your physician first thing in the morning.