I experience this sometimes, maybe from a different cause. These don't always work, but sometimes they do and I figure that's better than nothing.
A timed message that you've copy pasted from a vent or something made a while ago (I realize this doesn't help now if you dont have anything like that, but maybe eventually you will). My memory means I forget I set it up pretty quickly, but you could try sending it when you're really tired.
Depending on how bad it is, if I make it into a story or something I'm reading people can still express concern and once I know their general reaction that can make it easier.
Set up an aac board, your phone should work fine. I use AAC cboard (android phone, it lets you set custom images and responses), it has the connotation already of not being able to express yourself well right now if the person you're trying to get help from knows what it is. And if they don't, looking up 'aac board' can fill them in pretty quick. That way its just a button or even leaving your phone screen open in the menu.