I don't think a little extra activity is out of line after eating heavier, but it can certainly also cross the line into some form punishment or purging. You're definitely right to just pick up and keep going with your next choice if that feels healthy!
I try to use my mistakes as motivation to choose differently next time, instead of trying to "fix" them in some way. Somehow, knowing I'll have to live with the consequence (slower loss, more hunger, feeling bloated, whatever) is more of a deterrent than the prospect of extra exercise
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