IMHO you have a sensible head on your shoulders and though you are in shock about this, you have a strong heart; you must have, to have been able to do what you just did.
As for believing it, well disbelief and shock go hand in hand in grief. IME time is usually helpful in making us accept the circumstances. I hope your healing is as quick and as easy as it can be for you. I wish for you to get what you want and what you need.
Let us know if we can help, we all feel for you.