The site says I'm using 13 of my 13 pet slots, but since I don't have a Gold Account anymore, would I keep my 13 slots if I abandoned a pet? Or would I 'lose' a slot until I bought another GA medal? I know the site used to be like that sometime last year, but I haven't been on in forever, so I'm not sure if that's changed or not. :'0

Pet slots are no longer a GA perk. In other words, you should have access to all your pet slots with or without a GA.

GAs and petslots are no longer related in any way. You have 13 slots, period.