Mally, that sucks and I know what you're going through. In my college years I had a major knee injury with a full ACL tear, 60% PCL tear, and a fully torn MCL. That lead to two reconstruction surgeries, two scopes, and two micro fracture surgeries...............all from 1979-1989. In 2006 I had a full knee replacement, followed by a staph infection in the bone 5 months later. This lead to an unsuccessful emergency surgery attempt to kill the bug. Eventually, they removed the knee joint for 11 weeks, and then put in new hardware. I also had two 6 week stints with a "pick line" and IV drips each day. I was pretty much a mess for almost a year.
In the old days, the time on crutches was much longer than today and I've spent a combined 14 months of my life on crutches. I was good on crutches, but then again I was a younger man then. I wouldn't want to do it again. You'll get better on the crutches if you get out and about regularly.