Yes it may very well be her meds (adderall in many people causes something nicknamed "adde-rage") HOWEVER... my non medicated adhd/2e 8yo boy has a lot of the same struggles right now.
It's painful to watch, because I can SEE what's happening as he tips into hyperfocusing and looping into negative spirals... but we are (oh so slowly) beginning to tip the balance. It is HARD work. In a lot of ways it's harder than "the terrible threes" which is the last time he had a cognitive/emotional leap and integration... but in some ways it's easier. The harder is that he trusted me absolutely when he was 3... as an 8yo half of his independence seeking is the whole NOT trusting me. So it's very, very slow going... but we're getting a lot more "aha!" moments as something clicks.
((One of the reasons I'm avoiding meds with kiddo ... although the past couple months have *seriously* made me rethink the easy button from time to time... is that learning how to self monitor and pull yourself out of these spirals is something I want to teach before we give him the choice of meds or no meds. We only have that luxury because we homeschool. He can get up out of his chair as much as he likes unless we're standardized testing, and those are rare. But even being adhd myself, and having a strong edu background in ADHD it's sooooo hard some days. That ability to self monitor and to "yank yourself up by the collar" is one of the major differences between being bipolar and being adhd. Bipolar people have NO control over their mood swings, adhd people can learn how to moderate them to a degree... esp if they catch them early. Not that we can stop the swinging... but that we can stop a series of emotions in it's tracks once we swing into it. It takes a lot of practice, however.))
These "the world is ending" type spirals are a common facet of adhd. Our emotions are ALWAYS intense. Either we're intensely happy or intensely upset. Intensely excited, or intensely terrified. The RIGHT med mitigates these (almost but not quite bipolar) mood swings. Of all the meds I've taken over the years only TWO didn't. One made everything worse (one of the amphetamine group meds, I forget which, but I'm thinking it was dextroamphetamine) and one made me sick to my stomach whenever I was happy... so I learned to stay upset so I wouldn't feel like throwing up (ritilin... also known as metadate) So the fact that she's tumbling down the rabbit hole at any provocation tells me she's not on the right med for her, or not on a high enough dose. Either could be the case. If you up the dose and she gets worse... it's the wrong med. If you up the dose and your happy "take on the world!" child returns then it was just too low so she was getting sucked down.