Anyone experience this?

My average cycle length is 28 days and my average period length is 5 days. However, in May, my period shortened to 3 days and has done that every month since. Additionally, I am getting 4-5 days of brown sporting before this fairly light 3 day AF. Since this has occurred, I also have a weird feeling on my left side of my lower abdomen, it's not pain, just a weird feeling that is hard to explain, that comes and goes. Anyone ever experience this? I'm dumbfounded and will be making a DR appt soon!