Not able to perform

Hello. I am 25 year old Male. So here is my issue. I have been watching from a long time, I guess may be since when I am 13 years old. I got so addicted to the pleasure, that I started masturbating 2-3 times a day (not on all days, say 100/365 days). Even on rest of the days I masturbate atleast once a day. There are days, I used spend hours watching porn, masturbating 5-6 times a day. Everytime I masturbate, the first time I end up spending some time rubbing and stroking the penis. But the next times mostly I end up cumming without even getting the dick hard (say in 30 sec – 1min). But spend hours watching porn (2-3 hours a day). Every time I watch porn, my concentration would be get to climax and feel the pleasure. I like the pleasure so much. Did not conentrate about getting the dick hard or any other circunstances, just pleasure.

So recently I had a fling with a girl from my college. We decided to have sex, but I was not able to perform. My penis which was hard during the foreplay, all of a sudden went a little softer (not hard enough) to penetrate. So we stopped and tried another day, this time the dick got hard but I ended up cumming in 30seconds. And my dick did not get hard for the next time even during foreplay. I told her I am going to use washroom, started watching porn to make sure that my dick gets hard. It did get hard, but again got softer during penetration. She is a good girl, told we can work it out together. Thought to ask you to see if there is any problem with me. Should I be consulting my doctor. Did watching porn ended up getting me in this situation.