So today I tried to stop at a stop sign at the end of my street and realized it was almost impossible to stop. My car ended up stopping in the middle of a 4 way stop, luckily there wasn't another car. I tapped on the brakes and they went straight to the bottom

. I had to push the brakes very hard to stop the car. It was pretty scary having put your foot down and there was nothing.. I actually thought I was just gonna plow right through the intersection.. The "handbrake" light came on and turned around and drove back home.
I found a trail of liquid on my driveway and a puddle on my driver side rear wheel area. I saw it this morning before backing the car out, but I thought it was just melted snow from last night so never thought much of it. But now my garage is all dry except for that spot. And the trail of liquid was also on the left side. It looked like AC condensation drip trails when I look at my driveway. I looked at the x5 from the end of my driveway and see that the rear left of the car is sagging. The rear has been squeaking for a while, but it seems a lot of people have squeaks in their rear suspension so I never thought much of it. I was thinking could my springs have snapped and took out the brake line hence all my fluid dripped out so quickly? or could it just be a coincidence that both, springs and brakes fail at the same time?
I don't have air suspensions, and I tried looking up more information on this, but every time I search, it just brings me to a blank page. Today is "family day" in Toronto so nothing is opened, will get it towed to a shop tomorrow and see what really is wrong with the car.