I think some are too harsh on the OP who does not sound like a FF.
So first the obvious points as stated in other responses.
- Medicine should be in your hand bag.
- You should have some sort of insurance for delayed/lost bags. Sounds like you were returning home so unlikely to be compensated for late bags.
- EU payout from AC for the late arrival at your destination.
I can empathize with you for maximising your holiday.
AC is notoriously bad at IRROPs. The counters or phone lines are not staffed adequately even when they know there is disruptions like snowstorms. They rarely have more than 3 agents available airside for rebookings. They should at least provide a bank of phones connecting to the call center since it would alleviate the long lines for the agents. And many passengers are overseas passengers in transit who cannot or perhaps do not have a Canadian phone roaming option. UA has kiosks at several airports and also a few agents in the lounges (for those with status).
I do not understand the insistence by AC on staying the night in TO. Yes, your bags should travel with you but they were obviously late so there seems to be no real reason for delaying the OPs journey even further.
Could be AC was trying to get OP on a flight the next day since US CBP closes at 9pm (OP landed at 7.30pm) so they do not want to deal with the issue too late so the easy process is to get OP on next days flight as opposed to having him misconnect and then have to walk him out specially after US CBP closes at 9pm. Just my opinion which could be incorrect.