I'm sorry that you are still going through the painful process caused by this relationship that has come to the end. I was in your shoes once not so long ago, and I felt dying a bit day to day and wanting to be death to don't suffer the pain in my heart, my body, and to stop the river of tears.
This process is horrible, but at least there's hope at the end of the road. One day you'll be able to look behind and feel nothing about this person; nothing good, nothing bad, just nothing...
The most possible is that you will become a stronger person, and you will be smarter to choose the people that you want in your life.
I know is easier to talk from the other side, but try to don't focus on why he/she didn't give you explanations, sometimes the only explanation is just that people don't care enough, but if you keep thinking about, it will become in an obsession and will hurt you more.
Instead of torturing yourself with those thoughts, put in a box all the memories from that relationship, gifts, letters, etc. put them in a place where they can be hyde as you get to deal with the emotions, clean your eyes, and get focused in what is coming after this.
Be aware that all the physical and emotional pain that you feel is produced by a chemical reaction in your brain in response to the feeling of being left, but nothing last forever neither the pain.
Maybe, you are dealing with the worst part now, but one day not so far you will be feeling the opposite way, you'll feel confident, empowered, and free from all the crap involved into this sad story.