What about maybe trying to relax for a bit? Just take a few days where you try not to think about it. Just go to sleep with no intentions or expectations, then maybe write an entry in the morning in the Journal.
Who knows? Maybe your mind has gotten stuck in the mentality that it won't work? Just an idea, even though you say you don't stress over it :p
And if you can figure out why you're having trouble falling asleep, you might want to try and solve that - Maybe it has something to do with that.