Not new behavior, you've always gotten wound up about future events, like your get togethers with Dana and Limey. A significant event like family Christmas would always make you ramp up planning and anticipation. Now it's even more important, and you've more time to dedicate to it, because of not working and having large gaps in your social calendar. Add the stress of your parent's health issues hanging like Damocles Sword, I'm not surprised the tears come easy.
You can get all rational and shit, telling yourself it's silly and not a big deal compared to others' problems, but it's your safety valve. Safety valves are preset, they don't say hey, do you think it's time to relieve some pressure? Fuck no, when the time comes they do their thing automatically, and have no regard for time, place, or if they'll embarrass you in public.
So don't let it worry you, what you've been doing and thinking isn't very far from what you've always done. You ain't as crazy as you seem to think.
Well, no crazier than you've always been, anyway.