SAVE MY SEX LIFE PLEASE!

I'm 27 years old and have had problems with ED ever since an accident that hurt my neck and lower back.  Usually just issues with not being able to maintain erection, but worked for the most part.  Doctor first thought  I was depressed and gave me medicine to treat it... some months later, I advised him it did not help and it actually made me feel weird.  He took me off it and ever since I've been using Viagra, Cialis and whatever else is out there.  After taking those things were great again, but then the medicines started not working and the ED has gotten MUCH WORSE!  Now I can't even get a full erection.  DEFINITELY can't maintain a half erection for even 1 MINUTE, and now it's totally destroying my libido and WRECKING MY RELATIONSHIP OF 3 years!  My girlfriend new of the problem when we got together, I told her and she was ok with it.... BUT NOW since nothing seems to work even with medication, it's totally destroying my relationship.... we do other things to try and make up for it but it's also getting old.  If she leaves me how am I even suppose to maintain another relationship without being able to have sex???? I quit taking any medication for over 6 months now and nothing has improved, I've tried everything from watching porno, to masturbation and nothing is working.... I'm afraid my lil friend is dead... DOES ANYONE HAVE ANY SUGGESTIONS AT ALL FOR ALL NATURAL HERBAL MEDICINES? ANY IDEAS OF WHY THIS IS HAPPENING TO ME??? NEED HELP TO SAVE MY SEX LIFE AND MY RELATIONSHIP AND/OR FUTURE RELATIONSHIPS IF MY GIRL DOESN'T DITCH ME FIRST!   THIS IS NOT A JOKE! I'M VERY SERIOUS ABOUT THIS SITUATION... I just turned 27 and this is an embarrassing problem for me to have especially at my age! =(