I had the same feelings you did , somehow feeing irreverent by meandering through the possesions.... Never really feeling all that good about my purchases as if the favorable price to me is somehow a dishonor to the deceased or owner.
It has given me the strenght to use some of my prized fabrics more often since I reconginzed in the emotions after the estate sale part of my sadness or less than happy feeings came from the realization that yes someday that will happen to my "stuff".
I also made a resolution to stop saving stuff for "good" or the right occasion.
I guess it all comes down to that a quilters fabric can be profoundly personal as it relects the hopes and dreams of what it will become.