Weak erections and premature ejacuation.

Since last 6-7 months or so, I have been facing problems in maintaining strong erections and prematurely ejacuate which causes me dissatisfaction. Also i am not sure but maybe i feel my sexual drive is slowly reducing because of this. Also some 15 days ago, i experienced pain on the sides of my abdomen (flank pain) and on the recommendation of a neuropath, got sonography as well as various blood and urine reports but nothing related to any kidney or liver or pelvis problem was detected. So also i am facing problems in digestion causing acne problems. At times, my stomach / abdomen causes pain as if it is doing over duty to digest the food. I also feel low of energy and at rare times, my eyes get very little swolen/ puffy. I do have a stressful work environment. I am on no medication right now and do not suffer from any other severe problem. Kindly help me in the right direction as to what is the problem that i am suffering with.