I believe that homeguard has hit the nailon the head, it is quite likely that other matters ie: career or at home have loaded you to the top and the added stress of a bit of chop tips you over the edge. It seems unlikely that it is actually getting bumped around a bit would be a problem especially since as an instructor you would well appreciate the cause and effect of turbulence - unless it's the state of maintenance and age of the airplane you are flying that is really troubling you!
Go see your doc. the AME after maybe.