Try imposing limitations on your song writing.
Try composing using a very limited set of samples… try composing using only one note column… try composing a song without drums… try composing a song with only drums… try composing a song with your sound turned 100% off… try composing a song with only vocal samples… chose 3 notes and stick with them… don’t use the same note twice … don’t copy any patterns… use different samples for each pattern… and so on and so forth.
Imposing these kinds of limitations on your composition will undoubtedly lead to some interesting results, will help get you more in tune with music, and will hopefully inspire you again.
Also, when you hit a roadblock, click the “random” button:
http://music.hyperreal.org/artists/brian_e…ue/oblique.html
I’ll also chime in on the avoiding pot for a while and suggest that you try not smoking for a week, then composing based on what you’re feeling at the time 
Oh wait… disregard everything I just said. You’re screwed to begin with.