Help help help

I started my period while I was sleeping on September 10th so I woke up on the 11th and had my period all day, I had it 12th very heavy, and then the 13th very little and then today, the 14th im off of it. So I basically had it for 3 days and I usually have it for 4. I know I’m not pregnant because I had sex 2 weeks ago and I wouldn’t of got my period at all if i was pregnant and I used protection properly. So is this normal to have your period for 3 days instead of 4 like usual?