Menstrual bleeding 2 weeks after my last period...I'm bleeding again a week later

Background: 21F, 128 pounds, 5'6, no existing medical issues, no birth control ever, no / little smoke, occasionally drink. I have never had an irregular cycle and had a regular cycle around 31 days long for years now. Do not take any medications, just a womens multivitamin with omega I've been taking for 6 months.

I have my normal monthly Jan 22nd - 26th period. Normal medium flow.

Then I randomly got HEAVY flow and LOTS of clotting on Feb 7th and died down until about Feb 12th turning into more brown color. No big cramps, I did have slight slight hip pain. I was getting dizzy because of how much I was bleeding first couple days.

Last night, blood started coming again on Feb 18th. It's medium flow and bright red. Could it be that this is my regular period again?

Basically, do I need to go to the doctor? Should I be worried? What could this be?