If you really don't want an ASD assessment, would you prefer to change therapists? Because if she's talking over you, then that's really bad practice and certainly not helpful. Either way, you do deserve support, even if you feel like your problems aren't severe enough. I don't know you or your situation, but I've never heard somebody who's in therapy say 'I don't think my problems are bad enough for therapy' and thought 'yeah, probably not'. Whether you want your autism assessment is your decision, but it may be worth it just for the reassurance of self-knowledge. People may not know what to do with you, but at least you'll have a better idea of what to do with yourself? Or not. Your choice, again. I'm sure you've thought through the pros and cons at length. Anyway, your therapist sounds terrible, and I really hope that you can see somebody else ASAP.
Do you interview people before you see them? I interviewed about 12 therapists before choosing my current one. You are the service user in this situation, and it is OK for you to choose a service provider who suits you and, well, provides a good service. Seeing a bad therapist is somewhat of a waste; 'shopping' around for a good one is not. If you went to all that effort to get an ASD assessment, my advice is to keep sticking it out, because if you change your mind again in the future you'll just have to start the whole process all over again. That would suck.
I totally get that. Every individual's interpretation of that line (when to break confidentiality) is different, otherwise I'd try to give you advice, but if you really want to talk to her about this, you could always emphasise the 'not going to act on it' side very heavily. Even my idiot psychiatrist didn't freak out about 'suicidal ideation without intent', so maybe she'll trust you and not be shitty about it? Alternatively, you could always just phrase it differently - not interested in the future, loss of motivation, increase in depressive feelings, less able to cope with it, that sort of thing? Maybe? Like, if you want to talk about it without risking a breach of confidentiality.
That is just stupid, and actually ableist. I'm sorry it affected you this much, Alska :( I hope you fell better soon!
That's... really fucking cruel :/ comments like that add to the already-compounded marginalisation of people of colour who have clinical anxiety, while also being awful and ignorant about white people with anxiety. It's just an all-around terrible comment. Wow. I hope you feel better soon.