I was just wondering about some stuff in my life now which is confusing me a little. I'm 18 now.

I'll just very briefly write what's been going on...
Self harmed since about 11/12 years old (although remember hiding scars as young as 8 years old...just don't remember doing it so not exactly sure when i did start).
I regularly have suicidal thoughts and have done for years now (on and off..sometimes i go for a couple weeks without the thought entering my mind).
I've always been a big drinker since i first started drinking alcohol at 13 years old. (I've probably been sick/passed out over 100 times in the past).
Generally my mood is not very good as well. It's very unpredictable and about over 90% of the time is extremely negative and just horrible. I can't even begin to describe some the feelings when i'm feeling down in this way.
I also have a couple more dangerous/harmful 'coping mechanisms' which i wont go into here.

I went to go see my GP about some if this, mainly the self harm and down mood. It'd been quite confusing since i first went...she keeps telling me different things. First that i was getting an assessment at some hospital (not staying there or anything), then seeing a psychiatrist at the GP surgery and now this.

She is wanting to refer me to a specialist doctor who deals with alcohol abuse. I didn't even know such a doctor existed. She said it was a type of therapy or something...
Also she did mention she didn't think i was an alcoholic just that i do have some major issues with substance abuse.

Does anyone know anything about this type of doctor, what they do and what it's like to see one?
Does it sound 100% necessary for me to see him/her?

What the hell is going on?! I can't figure this out. I doubt anyone on here will either but it's worth a shot.
Just any information on the doctor i'll be seeing or what might happen next?

Thanks for reading. Please don't leave any mean answers. Trust me, seeing a doctor was the last resort and i did everything i could think of to try and fix things before seeking professional help.

Thanks!
x