So I have an anxiety problem (aside from the rest of my anxiety, which is much less focused and almost free floating) where I just cannot stand the thought of my friends being mad at me and my brain just goes absolutely haywire and assumes the worst possible thing (that they hate me and want nothing to do with me anymore).

My family wasn't /always/ dysfunctional, but we definitely were during my mid to late teens. For that time, I was the scapegoat of the family. Nearly everything that went wrong was blamed on me. I was the "bad influence" (even though I was actually a good kid) and the reason my parents were always arguing.

Though, I didn't really notice any like..... major problems with this brand of anxiety until the summer of 2020, when some stuff happened. One event was that someone (an almost friend) said that I made them uncomfortable and that I need to learn how to "read the room" before I talk. This and one other event (being kicked out of a volunteer practice because I'm gay) created the perfect storm and I fell into a depression for months afterwards. 
Ever since then, I noticed having much more pronounced problems with the "everybody secretly hates me" anxiety. I do think it ultimately stems from seeds planted in my teens, but it didn't really come out full force until that point.