No in the uk they are unlikely to go away. You may not end up in a psychiatric hospital as a result, as you would likely be referred to a crisis resolution team, a nurse would see and assess you at the general hospital, if you ended up there. They would help to decide how to help you best, they try to keep people out of hospital where possible nowadays.
Please seek treatment for your depression, things can improve for people, I have no doubt of this through my own and others experience. Its better to be active in seeking and getting help than end up being sectioned under the mental health act, although if neccessary this can save lives. If this was to happen to you, get legal advice and representation, you would be entitled to it.
Good luck