Too much stuff to carry / ship

I am packing to go back to school and the amount of things I have is ridiculous. I either brought too much stuff here or have acquired too much stuff since I came here or it's a mixture of both. I am going to lean towards both because I had to pay for extra luggage on my 2 suitcases when I was coming here (what I was carrying I am not sure).

Now, I might have to ship a whole box full of stuff just to be able to travel with only two boxes: this is insane.