I don't think anyone can tell you how long it will take you to feel well as every case is somewhat unique. This was my answer to a similar question yesterday: http://www.healthboards.com/boards/s...82#post2501482
(You would need to copy everything between the "url" tags, paste it in the address bar of your browser and go to that link to read my post. If you do that, you could compare my story thus far with yours to, hopefully, get a general idea of the process and the time it can take if your situation is similar to mine, underactive thyroid with no apparent complications.
My doc just prescribed a very small dose increase for me to 88 mcg Levothroid this morning and told me to wait eight weeks before coming in for another lab this time. I hope this one will have me feeling well by that time, but you just have to follow orders and do the time to find out. There aren't any shortcuts, apparently, and part of the process is healing from various lengths of struggling through life undiagnosed, not just the body adjusting to the increases in thyroid hormones.