Mark,
It took me quite a while and it wasn't as easy for me as some others that I've heard of. I was extremely right handed and had about 25 years under my belt doing everything RH. Luckily, I had only been shooting traditional for around a year when I made the switch, so I wasn't that good anyway! It took me 3 months of regular shooting to feel confident in my shooting but closer to 9 months to get the hang of handling arrows and such with my left hand without fumbling around and dropping things. During the first week, I remember some very large groups in the target from very close distances :D Also, I'm certain that I shot at least 1200 arrows in that first week alone.......I was determined to make it work!! Hang in there man. I think a lot of it is a mental game.....
Take care,
Jason