Brown period. Help??

Hi lady's!

So I'm a little worried. I'm 15 years old and have been having my period regularly for about 6 months. It usually starts with a little spotting for maybe a day and then continues with a steady, heavy flow. It usually lasts for around 7 days. But this month my period was around 15 days late and when I finally got it, there was just brown stuff on the pad (which I know is old blood) but brown stuff has been coming out like a light to medium period for around 3 days now. There was a tiny bit of blood on the 2nd day but no blood since. Is this normal? Should I be getting my normal period soon? Please help me!