Not hard, stopped watching porn and our sex is terrible

Im 20 years old. I have been with my girlfriend over a year and 6 months in our sex went south. My erections are very soft and I decided it was the porn. I stopped watching porn and its been about 7 months (just relapsed for the first time today) and still our sex is terrible. While on my back my erection is on my chest. Its possible to have sex im just very soft...And the few times I am hard I finish in seconds. I went to the doc about a month ago and he said oh youre just stressed here is some herbs but I am thinking about going to a specialist. Any ideas?

Today when I relapsed, while thinking of porn my mouth was literally salivating. And after I was like what did I just do..