Thank you for your replies. I had under 2 hours in the end, and made it into work for long enough to get some essential things done before coming home early so I don't end up off sick tomorrow (too much to catch up on if I miss even a day).

It's yet another reason why I clearly need to bite the bullet and ask for/demand some proper help. I was referred to Health in Mind, but after they took nearly 2 months to contact me, combined with seeing on their website that they can only help with "mild to moderate" problems (and not bipolar or anything so 'complex') I no longer want to pursue this route.

What I want is an appointment with a pdoc who can help me make sense of what is going on. I'm hoping this will happen soon. Last night I felt like if there had been sleeping pills available, I would have just continued taking them until shutting down. This concerns me when I don't actually want to kill myself (just to stop sometimes) and I know for a fact that the consequences would be unpleasant as I've looked up the effects of overdose for this particular pill in the past (in the hope of avoiding that urge).