Help on nexplanon


So I’m on nexplanon and have been on it since July 27th after having my baby in June for the last 2 weeks I’ve been moody and emotional and itchy all Over no rash and feeling sick at night I’ve had back pain and cramping is this from the nexplanon ? I was itching at the beginning of my pregnancy last year please some one tell me I’m over reacting and it’s probably just from the nexplanon I highly doubt I’m pregnant because it’s like 99.9 % effective