I personally wouldn’t raise it tomorrow.
But I WOULD think whether there’s anything you could ask for that might make you feel bit better, and then ask for that but spin it in a positive light for your boss...just to make things a bit more bearable while you look for something different.
e.g: maybe working towards new qualifications would give you more interest and motivation, plus bonus cv points in your job search? Ask boss to support with course fees and/or study leave, because career progression...advantages for the dept...blah blah
Or could you ask for some team projects from time to time so you’re not always working alone? I think it’s perfectly ok to mention that you’d like opportunities for a bit more team interaction, it’s really hard working alone all the time.
Don’t know if you’re full-time or part time, but could you afford to drop a day p/w and would they consider it. Extra time for job applications, having a lay in, a 4 day week would make a world of difference (I wish).
Etc
So if there’s anything you can think of that you could change that would gee you up a bit, ask for that. But spin it in a positive way for employer if you can.
Any of the above would just be a sticking plaster to cheer you up while you look for a new job.
That’s what I’d do. Good luck, hope you feel better soon