Confused

Hey everyone. So last year i had my period on 13Dec lasted 3-4days. My cycle is usually between 28-34days but then suddenly on 1st Jan 2018 I got my period again meaning I had a 19day cycle So now im confused bcoz I dnt knw if Im going to get it nw aftr 19days or will it go back to being between 28-34days. had intercourse on 14Jan I have also experienced light/wine red spotting since Thursday 18Jan. have anyone been through the same thing.