How long will it take for me to be back to normal after my colostomy is reversed?

Depends. Every patient is different but on average anywhere from 2-6 weeks assuming you are on a regular diet and having normal activity levels.
It depends. If you needed the colostomy because the rectum was removed then bowel function can be irregular for up to two years. Sitting on the toilet for a longer time will help the "new" rectum empty. If you have your rectum and had the colostomy for a different reason, bowel function usually returns to normal in 3 months.