Should I Get Help??

I’m in high school and currently on my 19th day of bleeding. My period just ended and then less than a week later (on the 12th) It started again.

I don’t know why this is happening because my periods have always been regular and I’m not on any birth control that would change my cycle. All throughout the first two weeks the blood was brown.

Do any of you know what’s happening or if I should get help? I told my mom but she said I was probably fine.