HELP with potty training regression issues! I'm at my wit's end!

[shannipoo714]

  My 3 yo has been sent home from preschool 3 times in the past couple of weeks due to pooping her pants.  She can't go back right now.  I'm taking her to the doctor Friday to rule out physical causes, but I'm not sure what to do.  Our next step is a psychologist.  We've tried rewards, punishments (taking away tv, computer, outings), sticker charts, money, etc, etc.  She was fully trained by 2 years old and now she's regressing.  She's also been acting out more.  I'm so frustrated! I just want to help her!