I'm not sure it's as bleak as all that.
"Thereafter, Powell moved to set aside his plea bargain on the basis that the trial judge had failed to properly advise him of the consequences of entering a guilty plea to manslaughter. The trial court denied the motion. He appealed from the denial to the court of appeals which reversed the trial court and held in a memorandum decision that Powell should have been allowed to withdraw his plea. State v. Powell, No. 900202 (Utah Ct.App. Oct. 24, 1990) (mem.). On remand to the trial court, Powell withdrew his plea."
FindLaw's Supreme Court of Utah case and opinions.
So there is at least one set of grounds for withdrawing a plea bargain, there may be others.
Hence, the suggestion to consult a criminal defense attorney.