PPD or burnout?

I am a first time mom with a beautiful 8month old and I can't tell if I have ppd or if I'm burned out from 90 hour work weeks during tax season. I literally feel fat and a total failure at life. I still work all the time and am so exhausted I feel like I have no energy for my daughter, my husband, and have no energy to try to get back in shape. Is anyone else going through this and if so what did you do?