Gray tabby cat with orange collar

I'm really worried - my gray tabby cat Milo is missing. He's medium-sized, short-haired, with white paws and a distinctive orange collar with a tiny bell. There's a small notch in his left ear and a white patch on his chest; his tail has dark rings. I last saw him yesterday around 6pm near the parking lot behind the Kenosha Public Market on 56th Street by the lake. Milo is mostly an indoor cat who loves sunbeams, and he's been shy around strangers this week. He means the world to me, and I'd be grateful to have him back if you've seen him.