I have taken 800mg of ibproufen for 3days twice a day. since then i have had dark colored runny bowels and now pain when i pee with blood in discharge?

Possible Nephritis: This is very unusual. You may have developed allergic interstitial nephritis (AIN) which is basically an allergy to Ibuprofen which primarily affects the kidneys (not skin). It might be something else entirely. Drink plenty of fluids as you go to the ER and get checked out. The 1st test to confirm: urine microscopy to look for eosinophils (type of white cell). Go see a doctor, it could be serious