Cycle changing?

My cycle has always been 29 days and my period 7 days, with very few hormonal mood swings. For the past 4 months my cycle has been 32 days, my period 5 days and I've had the worst hormonal mood swings and outbursts. My period has always been light the first day, crime scene the second day and normal for the last 5 days. Now it's crime scene the first day and light-nonexeistent for 4 days. I'm 23 by the way. Has this happened to anybody else?