My period came on march 3rd & ended march 8th

Patient: My period came on march 3rd & ended march 8th i had protected sexual intercourse march 14th . I also got fingered march 27 bled kinda heavy afterwards and it was a pale red color the next day. My period calender said i start my next period is march 31st but i have a 27 day cycle how is that possible ?now i am 4 days late for my period i counted on my fingers i come on the 4th . Im really worried!!! I have never been late 4 my period before

Doctor: