Breaking up is very hard to come to terms with. You believed that you found the partner of your dreams and that you would both be happy together for the rest of your lives. If only everything in life could be so simple, yet breaking up is a fact of life and differences often open up cracks that were not there before. It's heartbreaking, usually more so for one person than the other and that can leave you in a very lonely place.
Feeling vulnerable and raw after a break up is natural, it's part of being human; what is not natural is for you to suffer this pain and grief by yourself. Many, many people have gone through this process of breaking up, but they have come to terms with it and learned the best ways to move on.