i just completely wasted an otherwise great day

It sounds like your body needed the fuel and your brain just grabbed what looked good at the time. I know sometimes I won't really feel very hungry, but know I need to eat and once I start eating, my body seems to be like "oh, yeah, I'm starving, let's eat everything in sight, lol"

One thing that works for me is to prelog my food and snacks as well as planned exercise for the day as much as I can. That way I can eat steadily through the day and not be left with a huge surplus to fill in the evening.

The reality is, you did have the calories to fit in the twix and poptarts, so it's really not that big of a deal. Sure, they weren't the best choices, but neither is consuming only 1000 calories in a day. Keep healthy snacks around that you do like for evening munchies. Some of my go to snacks are peanut butter with a little honey on a rice cake, an apple with Greek yogurt that I'll sometimes mix peanut butter or honey or granola in, a couple squares of dark chocolate, popcorn, or nuts.