Nexplanon side effects

Hello ladies. I've posted about Nexplanon a few times but I'm still uneasy with all my sides effects. I got it put in on September 1st and we still use condoms as well. However, the whole month and a half of having it I've experienced every pregnancy symptom in the book. I constantly have cramps, sore breast and Nueasea... Is this normal? Also, this morning I woke up and had pretty noticeable veins on my chest? Could I still have gotten pregnant some how? (Test said negative) but I'm still freaking out!