Its good to feel “odd” on yom kippur. Getting out of your “comfort zone” probably helped you submit yourself to hashem and daven properly.
You can always go to payless and pick up a pair of “shoes” that look like the real deal but are plastic.
As for goyim and their stares. People dress in all sorts of weird ways these days from pre ripped jeans, to outrageous colors to (unfortunately) practically nothing, body piercings, tatoos, shaved heads that crocs seem perfectly normal with a suit.