I'm guilty of compulsive online shopping as well. Lately, I've been visiting Etsy almost everyday and buying handmade nail polishes (which I'll wear once and then forget about completely.) Before the nail polish, my obsession was handmade hair accessories (which I'll wear once and then forget completely.) I assume I'm trying to fill the perpetual emptiness inside me and, like you, it works temporarily but then I'm left with the emptiness and nails painted the wildest of colors once the thrill dies down.