I have been taking Metformin for about 4 months now. I always had periods that were very regular, but drug out for 7-11 days. They were always this way - very consistant so I never knew anything could be wrong.
These past two months, my periods have started full on (I usually always spotted a few days before starting) and then stop after 3-4 days (stopped immediately, again I usually spotted for a few days after the heavy flow). I have never had a period that started and was over with in 4 days (It's SO nice!!!)
I also have been having exaggerated PMS symptoms that I have never had before. Last month was so bad I seriously thought I was pregnant (nauseous, mood swings the week before my period).
Weight is dropping much easier than ever also.

Have any of you had this same experience?

Well mine were NEVER regular before but they had the same length/flow issues as yours - always felt like they were never going to end.

Eventually - I think after about 10 months when my cycle length started normalizing I found that my period did actually shorten & the flow become more consistent. But I only had 2 cycles like that before I got pregnant so I don't truly know if it was going to become the new pattern.