problem with my Nexplanon

So, I have an arm implant for my birth control. This is the first time I've used this form of birth control. This is also the first time I have been so miserable I'm constantly imagining leaving my husband, leaving my family (four kids 6 years to 6 months) I haven't had Suicidal Thoughts, but sometimes I've been wishing for death. I'm wondering if my arm implant is affecting my mental health. Orcould it just be postpartum depression or what every is one step down from that? Or could it be both? Or could I just be so miserable that life sucks right now?