Don't know what kind of chocolate or when you took it but i take some 20g of pure cacoa nibs once or twice a week. For me it takes about as long as a cup of coffee to get it out of my system, so around 9ish hours. I can sleep before that definitely but if i track it i can see that up to 9 hours after eating i get only light sleep.

If it was easter chocolate goodness and not (near) pure cacao you get the sugar and whatever else. Hope it settles soon for you. Just ride it out..