Having the hardest time learning!

[steakfarm]

I bought a unicycle (Sun) on a whim a couple of months back. Was driving around, saw a bike shop, went in and came out with a unicycle. Just thought it was something I could try and learn over the summer. Well, I ended up being too busy (or too lazy) to really get going on it, but since the weather's cooled a bit and I'm back to procrastinating, I've really tried to be more serious about learning.

So far the only "accomplishments" I can speak of are that I can balance on it pretty well (I was falling on my ass all over the place and getting massive bruises everywhere at first) and I can go about 5 feet or so now.

That's really my problem. I feel like I've got the basics down but once I hit 5 feet, something in me just takes my foot off the pedal. And it's not even like I'm falling or anything (at least not all the time), I just step off for whatever reason. I can't get past that point. It's frustrating the hell out of me!

Is this common at all? At least has anyone experienced something like this?