37 years old, tubes clamped and late period……. Ideas!?!

I’m 37 years old, mom of 4. My youngest gets is almost 12. I got my tubes clamped 6 weeks after she was born. I’ve had a period every single month like clock work. However this month, I am currently late. No unusual stress, etc. I have not had any period symptoms yet either. I’m just trying to figure out what’s going on lol. My husband and kids think I could be pregnant, but I’m not seeing it. As a mom of 4, you would think I would know. Right? So far, I am 3 days late. Which again is not normal for me. I am always on time like clock work.