So, I've been doing vestibular therapy stuff for a few weeks now. One of these exercises involves bringing a stick with a red bead on it to and away from my eyes in a figure 8 pattern.

I hadn't done it in a couple days, but the last time I had, I was largely able to do it without any significant problem.

Yesterday and today however, I am now completely unable to converge my eyes and focus on the bead when I bring it close to my face. It's like my ability to converge has suddenly disappeared. What the heck.

Why is this? Is this normal? Should I be worried that I can no longer focus my eyes on things close to me? I don't remember getting any new injures or anything....