My period is usually very consist with the date it comes up on, it’s always at the end of the month starting from either 18th-24th, last year i did miss a whole month in may though, however when i get my periods they are always so heavy the entire time and they last 7-10 days. I got my period in december on the 20th and it lasted until the 28th. Out of no where I got my period yesterday and it is heavier than it is when it comes on time, but I have never been 11+ days early before and my side effects are different this time, i have nausea, and bad headaches and I have been getting dizzy recently.