Questions about recent mental health issues in my life, and potential treatment.

TLDR: 23[M] - Since my Childhood I’ve been dealing with attention issues that remained. I developed mood related problems in high school which did not get better. In the past 2 years I started hitting myself and having suicidal thoughts. I’m going to visit a psychiatrist but I dont know what to expect

So I’m 23 and Im going to visit a Mental health professional the first time but I dont know what to expect.

Since age 7 or earlier I’ve been having attention problems. I get distracted at everythig: my job (regular office job) or at school, or even when I’m watching a movie. I also forget everything. Appointments, details, what I wanted to do minutes ago. If I focus for an extended period of time (like in my german classes) I feel really exhausted for hours. This has caused issues at all of my Jobs.

My dad passed when i was going to highschool. My HS years were really depressing. I didn’t want to do anything, I didnt really socialize, I literally didnt go to parties and i rarely hanged out with anybody. I felt like nobody loved me, and i felt very sad all the time. This has got better overtime, but i still feel sad and its still hard for me to socialize. I also procrastinate even basic tasks in all territories of my life.

Also since age 7-10(or earlier); I’ve been having imaginary conversations in my head. I wouldn’t call this “hearing voices”. It’s more like outplaying possible situations in my head. Like when i was walking home from school I would imagine my teacher asking me about the contents of that days lecture, and me giving answers to them. Or if I had job interview/date/conflict i would imagine what questions the other person may ask me when i’m with them,and what answers I would give to said questions. This only happens when I’m alone and not focused, but it’s pretty common.

Recent self harm issues: In the past 2 years i developped self harm and anger problems. This happened while my jobs became more and more stressful. When I think of something that embarrassing or cringe I did - like being scolded in school by the teacher, or messing up something at work - I punch myself in my leg, arm, or face in an almost involuntary way. Like I think about how I fucked up at school and I hit myself as a reflex. It also happens after conflicts. I got into an argument with my mother today and after that I started hitting my arm and stabbing myself with a pencil. I also imagined screaming at her. I also felt extremely angry, I felt pressure in my chest, I felt very overwhelmed. I also think about killing myself. I do not make plans or really consider doing it. I do imagine the act of it, and i feel as if it was better if i wasn’t alive. This happens usually when I’m under sudden stress.

I believe I have some sort of attention deficit problems that needs medication. I’m also concerned about the imaginary convo and self harm thing. Is it possible that I have schizophrenia? When I visit my mental health doctor what should I expect? What is the most likely diagnosis for those two problems? And what would the screening and treatment look like? I’m sorry for the lenghty post but I feel really lost and I have nobody to tell this.

Note: English isn’t my native language, but I hope i was able to describe the problems clearly. Thanks.