People make mistakes. Everyone on this message board makes mistakes, not just you. Don't be too hard on yourself. At least you have had such a wonderful girlfriend in your life. Go tell her how you feel sincerely and how wonderful she is, but don't make her feel pressure. You never know what is going to happen... If you try and fail, at least you do your part. But if you just walk away and move on without giving it a try, you might regret later in your life, and have all these "what if" in your mind.