Not sure what to tell you since I too only posted my first thread this morning.
We will all backpedal because we are only human and fear, anger, regret will make us feel like asking questions and seeking answers although we know it is counter productive. Forgive your self! When you feel these questions coming leave the room as fast as possible. Whatever you do, do not make a big deal to him about back pedalling. I think you handled it correctly.
Acting cheerful when sad? It is HARD. Maybe you can just listen to your favourite music through an earpiece or to some stand up comedy as you go about your chores. Read Archie comics! Whatever can put a smile on your face. Or just go to the nearest mirror and give a big old grin. It will make you laugh. Try green nail polish on one nail, purple on the next! You get the idea. If all else fails visualise OW having a bad bout of diarrhea without a bathroom nearby! Or without TP.
Make yourself laugh. It is hard but you are a survivor. So am I. I may get knocked down but as sure as the sun will rise I will get back up again.