Cauliflowerpower it sounds as though the portions you eat are fine. Congratulate yourself for stopping eating rather than beating yourself up for packing too much.
It takes a while to adjust to lack of hunger. Sometimes we’re so accustomed to really inappropriate portion sizes that we can’t envision a world where 1/3 sausage fills us up.
For me, variety is key. I’d rather have a little bit of everything in a meal rather than a massive bowl of anything, no matter how delicious. Which is why pasta as a main dish is often disappointing. Delicious, maybe, but the same flavours over and over.
Perhaps in the past, when you’ve been eating low fat and high carb, hunger has come upon you unexpectedly and you’ve panicked? Hence over-buying for today.
Either way—and sorry for over-analysing you, what a dick move—you’ve eaten what you needed and you smashed the water. So there ya go. 