I passed urine two weeks ago, i noticed 3 red spot (didn't looklike blood) the color was yellow next time i noticed a white watermelon seed covered with some red in pee. i drank watermelon juice 2 days prior no pain and normal since. is this serious?

What you described does not add up. You could not have passed a watermelon seed in your urine. If you have concern you should see your doctor who could arrange to get your urine tested. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV vaccine.