Period

Hi everyone! I'm 20 years old. And I've never been regular on my period, lately I was doing better, I had my period on September 15th and I had sex the next days (16&17th) and my period stop. I had sex again and in that moment I start bleeding again This was on September 28th  and it's still going on, I'm in period again!! Did you think this is super weird? Did anyone else has the same problem ??