What Causes Pink Spotting After Periods?

Q : I am not taking any kind of birth control right now. I had two missed periods, and when I finally had it, it was heavy. It s been a3 days now after I had my period and Ive been having pink spotting everyday, and also some pink stuff (like tissue) coming out sometimes. It sometimes looks kinda orange. I am really worried, I have no idea what is wrong with me. 126 5,6