Well now... sitting on your hiny for some long time, would have pressed down, i.e. reduced the swelling of your perineum and in the wider sense your vulva, which are swollen for some time post-op.
This swelling (in my own experience) is a bit like sitting on a small bulge. If that bulge get pushed more flat, all it really has to go is inside. All this would contribute to an initial reduction of depth, easily 1" or even more.
Will you regain it?
Partially after quite some time, since the swelling will further go down and thereby effectively create less depth.
Continuing with dilating over the weeks and month will eventually give again some more depth. If that will be as much as 1" I'm not sure. We are all different after all.
In any case your depth, as you state it, seems still very good at 6" or even 5 1/2" which is more on the deeper side for most natal females. Of course assuming you not 6'6"... or some such. The taller and large boned you are, the more depth and width seem to come with it also.
I'd say - nothing to worry...
Axélle
