Long nonverbal shutdown how to help

Hi

My 23 yo autistic daughter is normally copiously verbal. She has had some shutdowns before where she has been nonverbal, struggled to respond with gestures and been in bed. These have lasted a couple of days.

She's now been nonverbal for 6 days, and not responding with gestures. To either me or my son. She is getting up and getting herself food, consciously avoiding us being in the same room.

I don't know how to help her. All the advice seems to say wait it out, but also that these would last a few hours to a day or so. This is now a week. I called the local mental health crisis team last night who came out, but my daughter locked her bedroom door - a clear no and the most communication I've had all week.

Any suggestions on what to do, or where I can get help? Really worried that she's obviously in some significant distress. 

Thanks in advance, 

Rachel