Annelise hi,
What could be happening is that you're under medicated.
Not that you're completely off and akinesic but that you don't have enough levodopa in your system to prevent you doing things like running forward with your upper body leaning forward and also falling without throwing your arms out first which is what is a normal reflex in most people and prevents them from hitting their head but in a PWP who is off or a little off this doesn't come naturally.
Lee