I used to do that all the time and still do to a certain extent. I feed off others' emotions - I chalk it up to being a highly sensitive person (sometimes called empath). I've learned to shut it off in the last few years because it is too exhausting to always take on someone else's emotions and never know what is truly me.

As for rapid cycling I don't think what you describe is clinical rapid cycling . I think it's quite normal to get excited to read replies and the disappointed to not receive many. I think as bipolar people it's difficult not to patholoizw every single minute of our day, but I was much happier when I stopped thinking about everything in terms of an episode. Now I don't consider myself in a episode unless my mood disturbance lasts at least three days and is I changed by external stimuli. Even then I try not to name a mood unless it directly impacts my life in terms of functioning. For example this last episode was definitely hypomanic because I spent a lot of money and did all of my typical hypo activities (new nails/hair, lots of reading, cleaning, etc), plus it went on for a couple of weeks despite a negative review at work etc.

I dunno I'm not telling you how to live your life just that I was happier not thinkif about BP every waking second. It's certainly difficult though.