I know it's heart stopping but
A. check for torsional cracks on the chassis on the top tubes as above the compensator as they disappear behinds the body just under the cowl. You'll need a flashlight for the inspection.
B. Also ensure the body is still riveted and taught at the rear and none of the rivets have broken free or are loose - where the wood subframe takes hold.
C. Check your coil bracket is still attached and not cracked loose.
I hope it's none of these and something really simple but you still need to do the inspections regardless.
Good luck - Rgds Mark