I remember a couple of my friends knew I was manic before I even realized it during my last manic episode. I had memory gaps too, but I do remember going to a friend's house to hang out with her, talking a mile a minute barely taking a breath, and then it just kind of clicked that I was acting weird and I said something like "I'm so sorry, I just really really NEED to talk right now! Not even about anything, I just NEED to talk." And she just patiently said "I know."

It's kind of hit and miss though. Friends who have had some sort of experience with a friend or relative seem to catch on when I'm manic or depressed, but I work so hard at hiding it that some people have told me after the fact that they thought I was just "happy and excited" or "just sad".

I think before you think about damage control with your friends and coworkers, you should work at catching your manic episode and bringing it under control before it gets dangerous. Meds/psychiatry/meditation/therapy/support groups/friends.... whatever works for you. Call your pdoc. It's MUCH easier to mend fences with the people who watched you crack up if they know you did everything you could to be responsible and help yourself.