Postpartum Depression?

How long does postpartum last? I had a stillbirth end of June this year and since then iv been struggling mentally. I have a hard time sleeping and iv been mentally exhausted. I literally missed three days of work to re-evaluate my mind and let my mind rest. Hard for me to get out of bed too. Im trying not to think negative thoughts but its getting hard, maybe i need help? Im so tired. Is it possible this is postpartum depression? I feel like before i was pregnant i could manage my depression better but now it feels so much harder.