Travel Day (Day 0) - Travel Goes Bad

Not writing much as not in the mood. Been up over 24 hours and our flight to Montreal cancelled. 2 days before they can fly us from JFK and can't even get confirmation that car hire will hold for us.
Bad weather means nothing from airline so leaking money in  hotel stay overs and cancellation losses.
This has not begun well.

----- edit: written following day ----

Day started well enough,though early. Up at 03:30
Taxi at 04:10, only a 20 min ride on the new bypass so in the airport as check-in opened. Everything went swimmingly and through Security and near gates far too early really. Boarded MAN-LHR flight promptly and arrived 5 min early at Heathrow. We had thought of eating but had to transfer between terminals which ate into our 90 min and it was time to join check-in. Our second flight of the day also ran to plan with an excellent meal served and large measures of white wine sloshed out of a litre bottle.
I started off with a space invader next to me but to my relief he drew his arms in after a while and we both had as comfortable as one can be in an aircraft seat for 8 hrs. By now very tired after early start and couldn't focus my mind to read so watched a rubbish movie, deliberately, and tried to doze but it really dragged.
US Border Agency was atrocious with 40 machines followed by 2 agents, one which promptly disappeared. About 40 min later we exited finding out checked luggage standing in a hallway. We collected this and progressed to check in for flight Montreal.
First sign of things to come; my home printed boarding card failed to read but this was fairly quickly resolved and new ones printed. Remind me to put printer on Best in future.
Our more than 4 hour transfer time at JFK extended as the 5:30 pm departure fell back first to 6 then to 8. We were trying to decide to eat or not to eat when the dreaded change to CANCELLED appeared.
The rest of the evening and night were a blur of sick feeling panic. The agents trying to make re-bookings and the beat they could offer us was the same flight two days later leaving us with our Montreal hotel booking lost and our car rental - the core of our holiday at risk as we would not arrive.
Alarmingly, because the cancellation was due to weather, American Airlines were to give us no support, we were on our own.
Waiting at Help Desk where we had been told to go for hotels we were advised by another member of staff that even with cancellation discounts we would get cheaper if we booked outside the system and got ourselves a hotel for $124 via Booking.com; a short free ride on the skytrain then a call to the hotel brought us a shuttle so at least we had a place to sleep.
In excess of 26 hours since we started the day,we spent the evening throwing ideas including Greyhound bus and trains about, and tried desperately to contact Thrifty via Holiday Autos, even through twitter. By the time we gave up, it was too late and we were too tired to walk out to get food or drink and we hit the bed too tired and stressed to sleep well.
We ended this day feel lost and desperate and thinking how much extra money re-booking lost reservations was going to cost and what sort of mileages we were going to have to drive to catch up.