You need a new mindset - shopping is NOT fun!
Shopping is a waste of valuable time, going to crowded, noisy, dirty places, with lots of badly-behaved teenagers and screaming kids, having to struggle with public transport, or find (and pay for) suitable parking, having to carry all those heavy bags . . .
Your weekends are too precious for all that. Weekends are for lazing about, reading the papers, doing the crosswords, sorting out the cupboards, cooking new recipes, visiting art galleries (sometimes free), going for long walks, going to the library and finding new books to read (free!) . . .
Shopping is what other people do - you are far too busy doing much more interesting things!
Now just keep telling yourself that, and sooner or later you will find you believe it.