As a low time PPL student, on perhaps my 3rd or 4th solo, I got into exactly the situation Dennis describes in an R22 so I guess it might be more common in helis than may be thought, if indeed it was dutch roll I experienced.
It scared the cr*p out of me. I'd just turned and moved forward from the heli playground at Thurxton to face the runway and call for crossing when I got into this state. My response was instinctive and wrong - I hauled in power to get away from the ground and stuffed the nose down to add speed. Ended up crossing the middle of the runway at about 50 feet and 40 kts rolling and waying madly, zooming over Fast and pretty much doing something like a descending quick stop to get back into some sort of shape, with of course no call to ATC. How I didn't stuff it up, I don't know. Happily, no-one noticed, or at least, no-one said anything
ILAFFT! Quartering winds always get my attention.