Hello dear Understand your concern There are medical problem and psychological problem that cause erectile dysfunction. Medical problem are: hypertension, alcohol, smoking, prostate pathology, obesity, diabetes decreased testosterone. Yes frustration cause erectile dysfunction. Do not think too much as it cause psychiatric problem. You have to consult the psychiatric and do the following tests: blood sugar, lipid profile, color doppler, health check up, PSA, hormonal test, semen analysis You can take sildenafil but after proper evaluation by doctor before 30 minutes of sex with paroxentine. Yes excessive use can cause side effects like warmth or redness in the face, stuffy nose, headaches, ringing in the ears and dizziness because of hypo tension. Take following advice: Start exercise and loose weight if you are overweight, stop smoking and alcohol, pelvic exercise like kegel s exercise, hold urine for sometime before urination, start comfortable position for sex (women on the top may be useful), take healthy diet and fresh fruits, Anti oxidant like CoQ, vitamin A, C,E also helpful, use double condom, engage more in foreplay before sex. Hope this may help you Best regards Dr. Sagar