How would you tell the difference between post partum depression or just feelings of exhaustion?

Post Partum. Ppd shows vegetative signs & symptoms in addition to exhaustion, such as sleep disturbance, appetite changes, feelings or despair, etc. And can last up to 6 months.
It can be difficult. It is easy to feel overwhelmed by responsibility and emotion immediately postpartum. All mothers, particularly new mothers, need a support system. With enough help, if you can get adequate rest it will be easier to see if you feel down because of lack of sleep, or if negative emotions persist. Any desire to harm yourself or baby is an emergency and should be addressed with your doctor asap.