Healthy 22 year old possible ED.

Ok i am 22 years old, workout 4-5 times a week very hard, in good shape, sexually active for a long time. Now all of a sudden i have a problem getting and keeping an erection.

This all started a few weeks ago, i noticed my erections were not as HARD as they used to be, and my sex drive was gone. I was the horniest person on this earth and now all of a sudden my sex drive is almost GONE. I am now at the point were i have to try very hard to get an erection even if a beautiful woman is lying naked next to me. Even when watching porn it is hard to get an erection. Although i am still able to get an erection, it is not very hard, and if the woman stops touching me for more than about 30 seconds, its GONE and i have to wait a good while before i can get an erection again.

Before this i was having sex regularly (4-5 times a week) without a problem. Just thinking about sex i could get an erection on command. I have read up as much as i can on this topic and have found nothing helpful. I do not think it is psychological, if anything the bedroom is where i am MOST confident, and i enjoy sex very much.

The only thing i can think of that has changed is a mid-lower back injury. My spinal erector and surrounding muscles are extremely tight on one side and the pain is so bad that i can not stand up straight at times. And my hip is slightly displaced. I am going to the chiropractor for this, but nothing has changed.

I do not smoke, drink , or do drugs. I eat very healthy, and like i said before workout regularly. I have made an appointment with my doctor, but i am afraid he will just throw me some viagra and say good luck. So anyyyyy ideas on what this could be? PLEASE HELP! this is freaking me out!

EDIT: one more thing my sleep schedule has been pretty screwed up, sometimes going to bed as late as 4am, but still getting 8-10 hours of sleep USUALLY.

Thanks!