I went from being a stud to an embarrassed pre-mature ejaculator iin?

About a month ago, if my girlfriend would say she is down for sex, I wouldn't even hesitate, I would strip her down and start performing. Now I have come to a halt in my life, and it taking a serious toll on me mentally.

Two weeks ago, I would be doing the same thing, except this time my penis seemed to be not working properly. I still got the job done, but it was not working like a platinum v12 jaguar motor like it usually does. The next time we tried, I could barely get it up. It was like working with a flimsy piece of rubber. Every stroke I could feel, it felt like my penis would bend, and I never had that feeling before. And this is when it started to torment me.

I want to take a detour and provide a little information about myself. This has happened to me before with a girlfriend I had about 4 years ago, but we actively tried using a condom, and for the life of me, my penis never worked. So, I figured it was the condom that was desensitizing my penis and the feeling was gone so I wasn't stimulated anymore-- boom, erection gone.

I have been with my current girlfriend for 2 and a half years now, and this happened to me in the beginning of our relationship. Except this time we didn't use a condom. This time , We could do foreplay perfectly and then when it came time to perform, I got nervous (because she is exceptionally beautiful, super hot, if i must say), and I was a little intimidated. I got past it; I blamed it on not being too sexually active prior to meeting her, and that she was too beautiful so I got nervous, and eventually got used to her and trusted her.

So here we are now, 2 years later, and it is coming back full blast, way worse than it has ever been before. I literally just tried about an hour ago and I couldn't even get hard. I was the one who wanted to have sex, I am perfectly attracted to her; she's the prettiest woman I've ever seen.

I think this is a psychological game that I am haunting myself with and I DON'T KNOW how to get out of it. I try to think of all the good times we had, past the point of my erectile dysfunction in the beginning, I've been thinking about how far I came from that time and tried not to look back, but it seems to be the only thing I can think of.

For god's sake I am 19 years old. It makes me feel... worthless, hopeless, embarrassed, and compassionate for my partner. I want to fulfill her sexual needs too, but it seems to bring me down knowing that, at this point, I can't.

If you need to know, I am, again, 19. I weigh 275 pounds, and I am 6'1". I am not morbidly obese as I am currently going to the gym 3-4 times a week. Could it be my diet? I am not eating all the vegetables that I should be, and often times I am eating junk food (diet sodas, chips, candy). Could this be a psychological form of Erectile Dysfunction? Or could this be a little of physical ED and psychological ED? Should I try some natural supplements, such as, Horny goat weed?

I am in desperate need of opinions and suggestions. Thank you for reading this post, it means a lot to me.