New shoes, feet immediately cramping

Hi all, after my first half marathon I realized I need to size up in my shoes. Went to a run store got sized, of course one foot is a monster and the other just a regular foot, and one foot has more room. Went to take the pair out for an easy run today and about a quarter mile in both feet are cramping. I’m pretty good on making sure I’m hydrated and fueled before a run so my best guess is the shoes are too big? Or maybe they’re too soft. I have the brooks glycerin gts 23. Anyone have any idea what the problem might be?