I'm trying to think what to say that will help.
Here are my suggestions:
First, you are still the same MadMommaMemoo 
Second, keep life as unstressful as you can - stress can often be a trigger.
Third, look back over your life with a kindly eye, noting how your moods changed and if they were normal reactions to events - everyone's mood varies, but in addition people with bi-polar have moods more extreme than others, or not related to life stuff.
Keep a gentle eye on yourself.
This is partly drawn from my own and friends' experience, partly from quite a good course I'm on, run by the local MH Trust.
Hope it doesn't sound too vague. It's just my take on how someone might begin to get their head around it, and is really a suggestion of how to reflect on the situation, by gathering information.
Have you got a hectic life?