Postpartum Period

Victoria
Hello all.. my baby girl will be 4 months on the 21st. I am EBF, I nurse on demand and throughout the night (every two hours at most).. skin to skin, cosleeping, and basically hold my baby all day. Everything that I'm reading says that I shouldn't get my period yet so I don't understand why I'm spotting. Any of you ladies have similar experiences? I don't mind.. just wasn't expecting it and would like a little insight. Thanks!