Yes, sorry, Mitchell; I confused your lesion with someone's else.
Please, disregard the previous lecture about the collar bone.
You are correct, in your case, it looks like the rear tire went into a skid, then the rear tried to catch up with the front swinging CCW and the left side of the bike trapped your left ankle against the road.
Your ankle probably got liberated before the bike slid those 80~100 feet and you rolled and slid on your own, damaging other body parts.
Regardless of the reason that initiate it, there are two types of low-side falls:
Due to front tire tucking (described in previous post): Note the pure lateral fall of the rider's body (hence the typical Clavicle damage:
And due to rear tire skid: Note the more mushy fall of the rider's body, with his but still connected to and following the seat that moves down and away from him, while his ankle becomes sandwiched by the bike and road:
A backpack tends to protect the upper back, shoulder and head in this type of fall.
Did you wear one that night?