hello there, a doctor gave me an involentary admission to a mental hospital, as a result, I can't have a gun. they said I threatened suicide but it was not involentary. DE requires a MD to say I am sane. any ideas?

firstly, why you need a gun?
anyway, you could get a lawyer and go to court and get a judge to order a new evaluation. But, DE law may not permit it.

as you said that you are having a history of mental illness i.e. not a protected class. An attorney might be able to tell you what actions you can take to remove the firearm prohibition. but it will be too difficult or bottom line may be that there is NO solution to the problem.