I recently did almost exactly the same thing. I'd switched positions within the company (a federal contractor) from one division to another, leaving the "intelligence support" division for the "engineering" division. It wasn't a good fit, and much like you I felt that I wasn't getting done what they deserved.
However, upon giving notice, that crushing guilt was lifted. Since I knew there was a solid end date, finishing the time was very bearable. And since I gave notice, other positions with the same company are still available. I can still use my coworkers as professional references (some of 'em, anyway).
If, on the other hand, I'd dropped the bomb and said "screw you guys, I'm leaving NOW," I'd have had to deal with the guilt of leaving both the contract lead and the task lead with a hard-to-fill slot and no warning. In exchange, I'd have had a relief from two weeks of ultimately bearable work.
However, upon giving notice, that crushing guilt was lifted. Since I knew there was a solid end date, finishing the time was very bearable. And since I gave notice, other positions with the same company are still available. I can still use my coworkers as professional references (some of 'em, anyway).
If, on the other hand, I'd dropped the bomb and said "screw you guys, I'm leaving NOW," I'd have had to deal with the guilt of leaving both the contract lead and the task lead with a hard-to-fill slot and no warning. In exchange, I'd have had a relief from two weeks of ultimately bearable work.