No Period For A Month

My Period Hasn’t Came On This Month & This Is The Last Day Of The Month ...My Last Period Was December 19-23 . I Took A pregnancy test & It Came Back Negative. My Period Comes Ever 35 Days & It Was Suppose To Come On Sunday January 28th ...I’ve Honestly Been Freaking Out . Idk What To Do Now, Could Someone Helpp !!!😓