Excellent song!
I agree with the comments here. It sounds like you have a bit of stagefright, which is not at all unusual. Uploading videos of your playing on youtube is actually a great thing, because you have an audience in a sense (though obviously a bit different than a live gig).
It also enables you to really listen to yourself and how you sound. It's hard to get a sense of how one really sounds when playing at the same time, so it's a great thing to record yourself.
But like Sander said, be sure to practice with a metronome (there are free ones on the net you can use).
And yeah, just practice, practice, practice. The more you know the song, the more confidence you will get. Practice it, and try recording yourself in a couple of months or something. Listen back, and see where you have improved and where you need more practice.
Also, try practicing the song with a plectrum. It might be hard to get used to if you haven't played a lot with a plectrum before (especially the riff), but once you're comfortable with it you'll be able to get the song to rock a bit more.