Mate, I am sure everything is fine and running will return to to normal gradually. You were forced to run after loads of walking, those muscles will have already been tired. I would think running ideally needs to be broken in gradually just like walking after the op, the muscles have slow and fast twitch fibres, also running will be stretching the muscles and ligaments of the legs, hips, pelvis and back more than walking - you need to retrain the body and mind how to run again! The muscles will be stressed differently and the hip/back may not be probably re-aligned to your new correct position. The joint is fine and you understandably have some muscle soreness, the running was awkward but you manage it and it will only get better gradually.
I think the treadmill with good trainers will be a good starting point but even the transition from treadmill to outside will work the muscles differently and there will most likely be soreness. Totally understand the frustration especially when your mates are depending on you, but you did your best and it will only get better, like walking, when you start running I am sure it will soon return.