Sending dirty pics to an Australian man has been known to cure that.
Seriously though, what's wrong with the jokes you've told here - "moved from the frozen wastes of Canuckistan to the greener pastures of Freedomland. Came for the weather, stayed for the deep fried everything" is gold, and "jesus, guns and freedom" could be tied into a strip about someone trying to hack a scientist's password - 'science', no. 'intelligence', no. Oh, he's American...
For me watching stand-up really helps, I find myself hitting pause to write jokes in the same style as I'm seeing. Mostly helps for writing stand-up though. Writing bad jokes can sometimes kick start things, even ones with no humour that just sort of seem like jokes. If you're broke you can sell them to the writers of Everybody Loves Raymond afterwards.
You'll get there, you can't lose your funny any more than you can teach it, but if it gets lazy you might have to poke it with a stick 'til it wakes up :)
So how's Freedomland anyway? I've heard tales of four storey shops that only sell M&M's and banks that give you a free gun if you open an account.
Dinosaurs had eggs bro, the chicken came way later.