Can sex change your period?

Okay so I had sex for the first time with my boyfriend on May 9th and my last normal period was April 22-28 (my period is usually 7 days) In the month of May I missed my period and in just it was the weirdest period I ever had. I was supposed to get my period on the 22nd but it came early. it started with a little bit of light brown stuff that ended up turning pink for two days and then it became bright red like my period (that lasted 3 days) and then after I just had that pink discharge for a day. I had small cramps and my back hurted during my period. but yeah my period only lasted 3 days instead of 7.