Sounds like you actually have too much work load; I would bench all the projects other than one, preferably the one which is almost finished.
It's a common cycle and I have actually been trapped in it a few times, however once you complete a project and it works well the satisfaction helps motivate you to do the same on your other projects.
Also ever thought about getting some help with the projects from friends etc...? it makes the process a lot more enjoyable when you have someone to help and talk with :)