Spotting after period

My period Is really irregular, but I know my period. I was on my period for about 5-6 days. I say 6 because the ending of my period are always the same dark, brown blood very light. The next day I was completely done with my period so I thought? Maybe? Later that night after all day of not bleeding I had a little spotting very very pink super light than it stopped, and the next day a little spotting very pink in the middle of the night, and I'm having cramps with this (this has never happen to me before) , Have anyone else had this problem or any idea? Also me and my fiancé have been ttc for about a year now.