Hello Shellb.
I can also feel my mood change quite rapidly, I sometimes feel it's like watching a storm gather and move towards you, you can see and feel it coming but there's nothing you can do to avoid it. Other ladies on the forum have described the sensation of a switch flicking and I've had that too. My menopause book says hormonal changes can be subtle but that certainly hasn't been my experience so far!
I hope your mood lifts soon and you begin to feel better. I know how frustrating and distressing this whole business can be and you have my sympathy.
Wishing you well.
K.