If your meal was SW it shouldn't have a negative effect on your losses. Consultants always say that you can eat a sink full of pasta & still lose, obviously we'd never do that. but as above, its important to eat until your full, don't force yourself to eat just because its there. Let us know how you get on x
If you overeat free foods at one meal, it's not going to matter in the long run - we've all done it! It only matters if you do it at every meal - you need to eat till you're satisfied, not completely stuffed, to protect your losses. You'll soon get the hang of it though!