Alot of things can result from childhood trauma. Another thing that plays a big roll in our lives is our sexuality and sexual tendencies. Have you ever heard of Nofap? It's an act of not viewing Pornography, masturbating, and and/or having orgasms. It's a way of seeing into yourself more. It aint easy, but it makes it alot easier to understand things alot better. Ever since I've been doing it, I've been finding out alot about myself, being careful of toxic people to hang out with, getting closer with God, more at peace, etc.... Theres alot of videos on youtube about Nofap, give it a look, I think it wouldn't hurt.
I think you're describing a lot of stuff here, some of it accurate and some of it stuff you've read on the internet that probably isn't true but you've internalized it. Marijuana doesn't "cause" schizophrenia. Although nobody knows how it's caused, it's believed to be an illness we're either born with or we're not. Marijuana can, however, bring out of us things that are buried inside us. It can be a very introspective drug. Because of that it often makes people very anxious. Meth obviously causes whatever is inside your head to go a lot faster, so for your brother it was a very poor choice. PCP can do this too. So if you already have a psychosis, taking any drug that profoundly affects the brain and our thoughts can make it a lot more vivid. That's not you. You sound like someone who apparently suffered some trauma early in life, and that can have lasting consequences or not depending on the person. We all have our individual personalities, and some of us are a lot more affected by things than others are. That's just how it is. What it sounds like to me is you're suffering from a pretty chronic anxiety disorder. Probably prone to phobias, given you've had trouble traveling. Might be some depression in there. But coming on this forum for professional help is the wrong place to look. We're mostly anxiety sufferers on this forum and some on here are here because they know anxiety sufferers, but this isn't a forum where mental health professionals hang out. For that you're going to actually have to see mental health professionals, and a psychologist for therapy would be a great place to start. If you ask you'll get a professional diagnosis and a treatment plan. If the therapist believes you're ability to function is not very good they will suggest seeing a psychiatrist for medication, and will probably give you some recommendations of ones they work with. Don't expect a quick solution, because you sound like you've been going through this off and on for a long time, so it will take some work and some time to get over it. Meditation is a great idea. But don't get so hung up on what you're reading -- it's very hard to tell when research you find on the internet is done properly or not. Marijuana is very difficult to research, because there are people out there who are almost religiously in love with it doing research and those who are pathologically opposed to it doing research, and both kinds of people produce bad research. Illegal drugs are very hard to research because most people won't talk about using them and don't report problems they have with them to avoid getting in legal problems, making it impossible to tell how good for you they can be and how bad for you they can be. Also, there's no such thing as "ocds." OCD is a variety of anxiety disorder, and the fact you've had some quirks here and there isn't OCD. When you have it you have it all the time and it's quite debilitating. Don't try to self-diagnose, and don't use colloquial usages of mental health terms if you suspect you actually do have mental health problems because you'll only talk yourself into things you don't have. So you know you get anxious about things, you know you seem to often try to find health problems you have, and you've had some experiences with your brother and alleged abuse you suffered when young and some thoughts you don't like having. Know that every living person has intrusive thoughts, and anyone with a mental illness has them a lot, so don't give them more power by giving them a name and qualities. In short, don't talk yourself into getting worse and worse, accept yourself and the fact we all have our quirks, and concentrate on fixing only the things that are making your life difficult to navigate.
I also forgot to mention. As I grew up and got actual friends and dates around like age 17 I started promoting at clubs and socializing I started to overcome all my phobias and ocds. And they didn’t bother me at all anymore. Except now and then again focusing on negative thoughts