Yep, been there, done that, from multiple European countries. As stated above, the postal service should have all the supplies you need, available for purchase. You might also try UPS, DHL, etc. but they may not be as convenient/accessible. Make sure that it's not going to sit on your front porch for days before you (or someone else) grabs it.
It's also possible that the package may take a while to get there, so don't send anything you'll need immediately as soon as you get home (I once sent a box from Morocco, by the time it finally arrived at my house, I had been back for so long I had forgotten that I sent it!).
You may find that the cost to ship that box is surprisingly high, but you'll probably pay it gladly to be rid of that extra stuff. Remember the cost -- it'll help reinforce that "pack light" voice in the back of your head for the next trip.