5 years is an awfully long time, especially since all your teen years, and young adult life has been with each other. I admire your courage, you did the right thing for yourself, as she was weaning herself from you, and keeping you in her life without responsibility, or commitment to you. Dumped but available.
You said what you meant, now you have to mean what you say, leaving her alone, and take this opportunity to explore your own world, and see where you fit without her. Be aware that it will take a long time to break free from the bonds and attachments you too have formed. Old habits die hard, memories haunt us, and we find ourselves lost, confused, and in shock!
But it also a time to figure yourself out. Sorry guy but that was the good news, and the bad is it's a difficult thing to get use to being on your own without her. Break ups suck for sure. And its going to be miserable for a while, but you will find other ways to be happy on your own, and be a bettor person for it.
These stickies may help.
Relationships - Ask Me Help Desk