I hear ya. My swings are really exacerbated becuase of both sleep apnea and Insomnia (related but distinct conditions). I'm going through it now - my CPAP machine hasn't been working for a few weeks - I've been trying every which way to get it sorted. And with sleep deficit, I get more hopeless and more deep Bipolar depression, huge Panic and Anxiety and lower functionality (and with that not being able to go out where I'd see people) - and I don't have anyone I can ask to help me in day-to day things. And because of all that I get much more lonely.

I don't have much good advice except to try to look at anything underlying - like for me sleep deficit - and then focussing on getting that right.