I know the exact feeling. I nearly cried when our robot was crated and picked up, and the next day, I was ready to go to robotics, but I realized that i wouldn't be working on anything like that til next year. I'm really going to miss working so closely with my friends and staying on campus so late.
Our math teacher assigned us the task of designing a simple machine, and to build a scale model of it, and I went nuts over it. I started drawing the moment I learned about it, and made plans for using motors and stuff
My partner told me, "You're having waaayyy too much fun with this, let's just keep it simple, k?"
I actually got really sad b/c I realized that I will only be doing this twice more before I go to college.
That's life. Now, to go work on that design for the math project...