If you go, go in voluntarily. Life will be easier for you. Getting certified isn't pleasant. You lose your rights and really cannot do anything until it expires or is cancelled. Some hospitals will even take your clothing.

Whatever you do, don't fight them. If you do they can "flag" your records, which means you will be listed as a patient with combative tendencies. Once this happens any little hint of uncooperative behavior is resolved with extreme measures such as injections and restraints. Once this is placed on your records it is hard to get rid of it.

The staff chart everything from daily visits to the amount of socializing you do with other patients (or inmates). It is best to keep to yourself especially since there is a psychiatric culture and a lot of competition between patients.

People are not usually admitted for self harm unless they are a threat to themselves.

If I were you I would try to work through the feelings and urges with you therapist and seek support from family and friends before considering the psychiatric unit.