dark ammonia scented urine

this has been going on for quite awhile but i have no other symptoms of anything? peeing doesn’t burn or i don’t have vagina itching or anything, but my pee smells very strongly and is dark. i’ve drank lots of water recently because i thought it was due to dehydration but nothing has changed. i’m sexually active and i don’t use condoms because i am on birth control. what could this be?