I'm glad your ok.
I don't know about Canada, but it sounds like it is 50/50 on responsibility. For one, you were travelling at a rate of speed which did not allow you to slow down in a safe manner causing you to swerve off the road. The lady in front of you was doing defensive driving as well. In my opinion, and if I were the cop showing up to the scene, I would award both of you equal amount of fault and call it a day. But if I had to award anybody more at fault it would be you since you were the vehicle in the rear. Anytime you rearend someone here in a America, it doesn't matter who's "real" fault it was, it is always the driver that hit the person in front of them.