Am i or am i not

So i had a light pink discharge for a few days and then it turned darker brown. It was fine strange and worried me a little but fine. I thought it could just be because i recently had my son and it was old blood. My period started not long after but my cramps were so bad i couldn't move and woke me up in my sleep. I have had sore Brest sence and feel very tired and sick just not quite natious. Any ideas?