If the package is sitting at your campus mail center, I'd call the mail center and ask who the package is from. You can also ask if they'd forward it to your home address.
This exact same thing happened to me last year. I was home on break and got an email saying I had a package waiting for me at school. I called up the mail center and (1) asked who the package was from, (2) asked the lady I was speaking with to open the package and read the letter to me*, (3) asked her to forward it to my home address.
*I went to a really small school, the lady I was talking with knew me and recognized my voice, and before I left for break I had warned her that I might receive an important letter or two over winter break. I realize that most mail centers wouldn't be willing to open your package, but they probably would be willing to forward it to your home address.