help?

So I got my period on Christmas Day (towards the end of the day) it lasted 6 days which usually it lasts 8 for me. It hasn’t been a month since, it’s been maybe 2 weeks and all of a sudden I’ve gotten a unexpected period which is tmi but all brown old blood and isn’t the heaviest, it’s starting to go away after 4 days. I’m not sure whether to see a doctor and or if this is normal?