I have okay erection and feelings while watching porn but not while i am having sex no feelings no erection. what do i do?

It may be worthwhile to see a therapist/psychiatrist to assess your mental health status. As an alternative you could consult a urologist. 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.

Please see your doc to rule out medical conditions first. Most ED among otherwise healthy young males is psychological, self-consciousness. Please see a a clinical psychologist or licensed sex therapist after your primary care doc. Peace and good health.