Blood drops with the urine

Patient: I am 17years old and since last 6 month a few drops of blood appears after the urine is over ,each 2 weeks twice maybe and i went gastroenterologist and he told me that there in no any thing in the urine after a test for the blood and the urine except that it is salty so he said you have to drink lot of water and a medicine to put it in the water and drink it he said it could help to dissolve it and he said that you may also go check a urologist and i don’t know what to do write know

Symptoms: Blood drops after the urine