I can relate to this. Part of it is I never go shopping into proper shops as I'd have to carry stuff home and don't drive so have to buy stuff on-line so just recently, some toast tongs as the old pair snapped; DD's Haloween outfit, an indoor airer for the winter. Then for myself, some new slippers, a top to wear to a special family party (not needed but 'completed' the outfit.)
I have a mirco-economy in my head that I have to have sold some stuff to merit buying any more (this is all Ebay stuff, I never buy new).
Bizarrely, I hang into stuff until they are on their last legs, will alter and patch stuff as I like to get the 'wear'.
If I look at my Amazon and Ebay purchases, it looks a lot. BUT I sell a lot of stuff on-line too and am currently decluttering.
I love browsing and finding a bargain, I love charity shopping too. I also like reading the reviews and putting up reviews myself.
I enjoy it BUT I think I need to reign it I though so have resolved so clothes this winter for me now as I have more than enough. I've taken up running again and I'm distracting myself with that now.
It is hard with Ebay and Amazon as a purchase is one click away!
I think you need to be kind to yourself OP, it helped for a while but maybe as others have suggested, some sort of therapy would help. The story about the Sunday evening catalogue is telling too, the shopping is recreating an inner nurturing feeling you had when you were a child. 