Confused...

Hello, I am about to be 32 next week... I always get normal periods. Me and my SO have been having unprotected sex for 6 years with no luck of any kind of pregnancy. He has 2 children from a previous marriage and I have 2 children from a previous marriage.... I get my period like clockwork every 28 days. This month I spotted a lot of brown 2 days before my period and had heavy to normal bleeding for one day and very light spotting the next day and period has been gone im on my cycle day 4 which it usually stops day 3 but continues.... im wondering if im starring pre menopause?? Idk whats going on. No other irregular symptoms.