I’ve taken a pregnancy test and it was negative so I know I’m not pregnant and I haven’t been experiencing any pregnancy symptoms. However, my period is about to be 30 DAYS LATE. I’m usually regular and the most i’ve been late is 2 weeks. Any possible reason for why this is happening?

Not on birth control or any other medication

Edit: I also haven’t felt any pms either. About two weeks ago i felt fatigue and headaches that I thought would mean my period would come soon but nope! I’m going to take another test soon