I feel like if I don't interact perfectly with my parents I'm going to lose all the rapport we've managed to build since I moved out and I'll be left with no one.
That's totally untrue. You don't need to be perfect to be able to keep your rapport with them. And you would not be left with no one.
Okay. She's responded now and she's calm. I was, as I haven't really said here, a really difficult kid to deal with from an objective point of view, so I think what was going on is a negative feedback cycle. I would constantly get in trouble for reasons I didn't understand or thought were stupid, would get angry and cause more trouble, get yelled at again, and I concluded that all adults were out to get me. I don't really know what to say now, or how to get past this.
Just explain " I didn't know why I was getting in trouble, so I got mad, got yelled at, and figured that adults were out to get me." You just need to talk about it, and keep talking.
How do I tell the difference between "explaining her side" and "shifting blame", and what do I do if it's the latter? She brought up that she would get scared of the tantrums I had when I was a kid and I remember I really was a pretty dreadful brat.
shifting blame is gonna be her trying say that it was all your fault, BECAUSE you were a brat. It's like the difference between "you had very loud dramatic tantrums, which scared me sometimes, and I might have gone overboard because of that" and "Since you were throwing HUGE, HORRIBLE TANTRUMS, I had NO CHOICE but to yell at you!" I'm not super clear on it, so I'm gonna mention @seebs and hope she has a better explanation if she's not busy.
Yeah, that sounds about right. And if you're afraid of losing rapport, say so, because knowing that you care about the relationship, and also her, will make things easier for her? Because I think it sounds to me like your anxiety here may be anxiety per se. In that I think she may be calmer and less upset about things than you're expecting, and that may tie into your weird expectations as a kid. So she may be very far indeed from being particularly deeply hurt, or wanting to back off from friendship, but if you're afraid of it, that's a real thing and she'd probably like to know. *thinking* I guess my point is, since you had problems when you were a kid because you were afraid of things and didn't know how to articulate them or communicate them, communicating them now helps avoid that happening again, and also shows that you're trying to improve the thing, which invites her to also work to improve it, if that makes any sense?
Okay, I will work out how to say this. She doesn't appear to be shifting blame, which is good. I'm just really bad at judging that and wanted to make sure. She does know I have actual clinical anxiety, so that'll help.
I think you're sorta automatically shifting blame to yourself preemptively, which is not a great thing, but that's the kind of thing anxiety does, so.