I parked my truck at my girlfriends for the weekend and when i got back and was fixin to head back to school i let the glow plugs heat up turned the key and heard a click. I think its the solenoid but i really dont know for sure Any Ideas?

Could be. Check the battery cable connections and starter cables.

Sounds like a typical battery connection problem, or some kind of connection trouble. Try jumping the solenoid, the one for the starter is on the fender.

I would check in this order:
1. Check Battery Connection. Either loose or corroded
2. Check Batteries, either dead or low charge. It takes alot of CCA to turn over a high-compression IDI
3. Check Starter Selinoid. Jump as mentioned above.
4. If none of these are it, it could possibly be the key cylinder - but I really doubt it. I bet it's either 1 or 2.
5. Check starter. Could be toast.

edit: you must have been typing when I was. Glad you got it fixed.

I went through it all but it was just my starter it still had the original starter but i got a new one today put it on and was back to terrorizing parkinglots and polluting the atmosphere.lol