Hi Jake,
Sorry to hear about your recent fall. It sounds like you have a relatively minor proximal gastrocs strain going on here. The gastroc (which is your primary calf muscle) actually crosses the back of the knee and attaches to the femur, so it can help the hamstrings to flex the knee. Regardless, the fact that you had no immediate pain, loss of function, or bruising are all good signs that this is something that will pass for you relatively quickly.
I would recommend starting back with a LP probably a little bit lighter than you think you need to, use a very slow and controlled repetition speed, and progress up in weight cautiously over the course of the next few weeks. If your symptoms continue to worsen with training, then see a doctor, but they will most likely just take an x-ray, tell you to rest, and possibly prescribe you some anti-inflammatory meds.
Keep us posted on how your next session goes.