I think your compression post may be giving way and it may be hidden from view. It should be located at the inboard edge of the door to the fwd state room, and at the edge of the fwd stbd bulkhead of the main salon. There are two accesses through the deck that will allow you to see the bottom of it, one in the main salon fwd and one in the fwd SR aft. There is a step under the compression post. The post in my 37 is aluminum but I believe most were wood.
Any way look there first. There shouldn't be that much compressibility in the deck
Good luck
Joe S