Before sex i have sexual feelings but as soon as i start after one minute the feelings die out and erection starts getting weak. what's the problem?

May be...: Based what you described, you might become the victim of sex overindulgence and obsession with situational environmental anxiety so leading to so-called psychogenic impotence. To help, see doc of expertise timely for counseling, adjusting frequency of coitus, improving environmental circumstance and interpersonal relationship and intimacy, trying short-term use of viagra, (sildenafil) etc.