Why is my 10 year old still crying?

Today was the first day of school, I walked my children to their cl rooms and said goodbye. As I was walking out, I saw my 10 year old heading down the hall, so I caught up to him and he starts crying hysterically about a paper he was supposed to turn in today. I didn't know what to do! I told him, "It's ok, please stop crying, you don't want other kids to see you crying on your first day, it's ok." Then I took him back to his cl (after calming him) to tell his teacher I would bring the paper in when I picked him up at the end of the day. It seems to happen more often in school, but it takes only the smallest thing to make him cry. He has been this way all his life and I have found no help in solving his dilemmas. He acts like its the end of the world and when he cries his face turns instantly red and he can't breath. Sometimes I feel it is completely my fault for babying him, or being too mean and now he is afraid of everything. My worst fear is that kids are going to make fun of him and start calling him names. He is in the 4th grade now and he needs to grow out of this. Someone please help!!