I'd say that "good enough" parents have many of these miscommunication incidents where because the parent isn't a mind reader, they guess wrong about what is happening in a situation, and there is a mismatch between how they would have responded if they knew everything the child did and how they responded with the limited information they had available.
E.g. when my eldest was young he once used my electric toothbrush to clean around the tap fittings. I was hurt and angry because I associated that sort of thing with someone being really disrespectful and I told him off. He was then really upset. Later after talking to him, I realised he didn't think about me then putting it in my mouth after he had done that and hadn't meant to upset me he didn't have the cultural context of people doing yucky things with toothbrushes as a bullying thing. He just found a really effective way to clean the sink and was proud of himself because he thought he had been helpful. I was able to put a replacement head on the toothbrush and he learnt not to use toothbrushes that people will put in their mouths to scrub stuff. No real harm done. It turns out later that he's likely autistic and maybe that played a part in him not thinking it through or being aware but maybe it was just because he was young.
I felt bad for over-reacting to him and upsetting him over an innocent misunderstanding. But in my head dirtying someone's toothbrush was a really disgusting thing to do and I felt hurt.
So I would say that it's not unusual for even good parents to have times where they don't understand what the child was going through and respond wrongly to them. Your mum in that situation may not have understood the sense of panic and abandonment you experienced, to her it was obvious she wasn't far away but to you it wasn't.
It was harsh on you when you were feeling like that to have that response.
But it may not have seemed harsh to her, it can be hard as a parent when you have a young child and feel you can't even leave the room to do a chore without them following.
But it could be that this incident kind of encapuslates the relationship, with her missing your emotions a lot (either through her own communication difficulties if autistic or generally being unsympathetic or lacking empathy towards you) and not offering enough emotional support.
Parents don't need to be perfect about meeting their kids emotional needs, relationships can survive mismatched responses. But if they are happening more often than not and she doesn't have the time, skills, curiousity or empathy to realise there are problems and repair them, then overtime it will damage the relationship and culumlatively you'd feel it as neglect.