Who is at fault in this situation?

I was in a car accident the other day, my brakes completely failed to the point where the pedal was on the floor, and the car wouldn’t stop. That caused me to rear-end a truck [this part was my fault]. We pulled over as far as possible and I turned on my hazards, and we got out to look at the damage. Her truck was fine, my car had a scratch, but I wasn’t too worried about it, so we decided to just go.
She asked for my number in case her husband decided he wanted to ask any questions, so I went back to my car to write it down.

As I was getting back out of my car, MY car got rear-ended by someone going pretty fast, which damaged both my car and the original truck.

The driver who hit me called the cops, so we were stuck there for a while, and now the lady who owns the truck wants to take it to court saying the entire thing is my fault.

Is it?