My thoughts are all over the place constantly and I don't know what to do to make it stop

I am an 18m college student and for as long as I remember my life has felt cyclical and pattern like in a way that I feel I should be learning from but for some reason I can't and it makes me very upset. Every single part of my life is ruled by irrational fear that feels like a cancer in my mind. I feel as if I cannot find new hobbies or interests or anything because its only a matter of time until it becomes dull, which is a thought that makes me upset and anxious. This has been a pattern throughout my whole life, where as a kid I would want something, I would get it, and I wouldn't like it. Now that I'm older nothing has changed, every time I try something I have the thought "its only a matter of time until I don't like this" and it kills any desire to do anything new or exciting and if I do go forward with it, I end up disliking it or not liking it as much as I envisioned. For example I feel immense fear that one day I will marry my girlfriend who I love very much, and that one day I will grow to resent her even though I have no reason to see why that would happen, I just feel as if my mind will turn that way even though I do not want to. I feel as if my mind is entirely in my control as anyone's is, but I do not know what I will want tomorrow or next year or next decade and it makes me afraid. I have always been afraid of things looking back, especially people. I do not understand people or what they want most of the time and most of the time I feel as if they secretly dislike me or, in the case of my parents, enjoy getting angry at me and seeing me confused. For as long as I can remember people have gotten upset at me for things that I cannot understand, especially my parents and from infancy up until now I have avoided sharing anything about myself with them out of fear of ridicule or judgement. I think this carries over onto other people where I feel as if I cannot be human around anyone except for a select few people. everything I say to anyone ever is run over and analyzed in my mind for every possible reason it could give someone to either judge me or think of me a certain way and I have always done this. My girlfriend is very helpful and kind and seems to believe that I am different than others and tells me that its ok, she strongly believes I am autistic but I do not know about that I have heard similar from others because of the way I act where I sometimes live in a way that is slightly unique and odd to some people with how regimented I am with it. for example I refuse to own a car more than 25 years old, and I have gone to extreme lengths to avoid it. I dislike using any sort of modern technology when an older simpler and easier understood equivalent is available and people have said to me over the years that this is strange and concerning. I would hate to be made to go to therapy or have to tell anything about how I feel with anyone especially someone who is paid to listen to me, as I know it would make me feel worse. I feel as if I am constantly lying to myself about what I want and how I think and it makes me so devastatingly afraid and I feel as if I can never trust any thoughts that I have. I know I haven't always been the soundest because I went through a few month long period of strong depression when I was 8 so I don't know if there could be something else wrong with me. I don't even know how this could ever be fixed but if anyone has felt similar please let me know what I could do. I am also very unsure if this is the right place to put any of this I am very new to reddit.