Hello Yukari: I'm sorry I'm not really able to comment authoritatively with regard to your concern.

But I noticed no one had replied to your post. So I thought I would.

(By the way, I don't have a lot of use for most mental health professionals either. My experiences with them have mostly been negative.)
My personal opinion, for what it's worth, is that the best place for you to start is with a therapist. (Of course I don't know where you live & that makes a difference.) But, at least based on my own experience, all most psychiatrists do is prescribe & monitor psych med's. It can take a few tries to find a therapist you feel comfortable with. So you may have to try a few out... sort-of like test-driving cars I guess.

I've never personally had any success finding a T I felt good about. However, I've read posts, here on PC, written by members who said their therapists saved their lives! So I presume there are great therapists out there. It's just a matter of finding them.
As far as self-harm & suicidal thoughts go... here again I don't know how much guidance I can offer.

In general, I don't believe people are hospitalized for self-harm. As far as suicidal thought goes, it really depends on the situation. If you're simply having the thoughts but have no intention of acting on them & have no plan, I don't think you would be likely to be in danger of being hospitalized.

On the other hand, if the mental health professional you see gets the impression you may be a danger to yourself, then yes I would presume hospitalization might be a possibility. At least these are my thoughts based on my own personal experiences over the years. I wish you well...