Yes, you can be convicted of disturbing the peace for this. Here is the law on disturbing the peace in your state, from the Nebraska Rev. Statuts:28-1322.Disturbing the peace; penalty.(1) Any person who shall intentionally disturb the peace and quiet of any person, family, or neighborhood commits the offense of disturbing the peace.Stating you are gong to "blow your brains out" is an intentional act--it is something that you only do or say on purpose (it's not an accident, like tripping while holding hot coffee and spilling it on someone). It disturbed the peace and quiet of your family (your mother and/or sister): it meets the statutory definition of the offense. That you were not taking you medication would not be a defense, because the law has repeatedly held that when someone with a mental illness who was on medication fails to take it--so fails to do the thing that will moderate his/her behavior--he or she is liable for the consequences of his/her failure to take a reasonable step to protect others from the effects of his/her illness.