i am 3mths post partum, everytime i lay in bed and when i get up from laying in bed, my lower belly hurts like when after i gave birth. it was hurting right after i gave birth, itd hurt when i walk or carry something heavy. but it didnt hurt anymore after a mth passed. 2 and a half mth hits and it started to hurt again, but only when i lie down and get up. its still hurting. what could it be?