Anxious, lonely, agitated...
With bipolar that can easily equal suicidal thoughts, it doesn't need a specific formula to rear its ugly head.
Anything remotely stressful or nothing at all, can tip us over the edge.
I've learned long ago to not fret about cause and correlations, to rather just accept that it is, and ride it out as best I can.
Sometimes its the only way for me to manage because I'm very logical, and bipolar is illogical at best.
Be kind to yourself, show yourself some empathy for the difficulties you're experiencing, and remind yourself that this too shall pass.
You've been here before and survived, you can kick this beast in the teeth again.
Take care