Is PIED my problem? Worried.. Please help!

Hi. I'm 19 years old and I'm trying to figure out if PIED is my problem. I've been watching porn for roughly 6 years and I haven't been able to achieve a firm, hard erection for months now. I can get aroused, but not firm enough for sex and it doesn't stick straight out.. It's limp. I watched porn 4-5 days a week, if not everyday. I'm worried because I don't know if it's my diet (which is poor) causing this issue or if it's from porn. While watching porn I have a hard time getting erect but can still cum.. This problem is very scary because I can't tell if it's physical or psychological. I never wake up with morning wood or get random boners throughout the day.. So my question is, is this from porn or should I go to the doctor?
Shall I mention, I've talked to the doctor and he said it sounded psychological and would run tests if I wanted to but he said he doubts it's anything like that, but he was just guessing.
I've quit watching porn for a week now and I've already had a wet dream. I could tell I was hard because I woke up with a pretty decent erection that went say quick, but i can never make myself get hard or anything. Please help.. I'm new to this and am very worried.