Welcome to the club. I had my ACL replaced with patellar tendon harvest and lateral meniscus root stitched back on April 6.
You will be in a brace and crunches for about 6 weeks to allow your ACL to heal but mostly to allow your meniscus repair to set in without re-tearing it. That part totally sucks and gets old fast but it works.
Do all the therapy. Do it at PT, and do it at home, as much as they will let you and you can tolerate. Follow their instructions.
Progress back will be steady, if you do the therapy work and integrate what you are allowed to do in your fitness routine.
I got some bands, some lighter dumbbells, a yoga mat, and did a crap load of ab work, dumbbell exercises, and full leg work like flutter kicks and scissors that don't require knee bending at first. Even push-ups with all my weight on my good leg.
Crutches are also goo exercise but you don't want to fatigue out your only form of mobility either.
You can eat a little more the first week or two to fuel your body healing, but then back off a bit or you risk weight gain.
Your quads on the surgery side will atrophy FAST. Don't worry. The therapist will help you build them back up when your knee is ready to start adding load. I'm a little over 5 months out and my surgery leg is about 90%+ as strong as my good leg. I can run, jump rope, do box steps and jumps, and I am working on agility now. I have almost full range of motion as well. It comes back, just do what the doctors and therapist instruct religiously and do as much outside fitness as they allow. I've got my Olympic lifts back to about 75-80% of my maxes. I've recovered faster than usual, granted, but just an example that you can come back well if you follow the plan.
As for pain, there was some soreness and discomfort once the nerve blocker wore off but it was never that bad. Therapy the first few weeks while you are stretching out scar tissue can get uncomfortable to moderately painful, but never sharply so.
