Doing Well, but Can't Sleep

All is going well.  My physical therapist has been working with me and he says I'm doing just great.  I give all the glory to God.  You see, I'm a very large lady and I was afraid it would be too painful to walk, but it's not.  The only real pain I have is my muscles in my lumbar region because I've been in the wheelchair so long.  But, I'm trying to work that out a little more each day.  Another small problem is that my stump is shrinking at a pretty fast rate, so I sink into the socket a little too far.  Last week I was wearing a 3-ply sock and now I'm wearing a 5-ply and two 3-ply.  I go in Monday for another adjustment.  All in all though, I'm very happy.  I didn't think I was going to do this (walk) for so long and now it gets a bit easier everyday.  Soon I'll graduate from a walker to a cane!  And then, I can begin to learn to drive again.  Do you guys drive with your prosthesis and is it hard?