Always exhausted, is it just tiredness or ppd?

My baby is 5 1/2 months now , I feel like I am ALWAYS exhausted , to the point my chest feels heavy and it feels hard to breathe when I need to wake up.. I started working again at 7 weeks pp. I work at a grocery store, its pretty physically demanding. My schedule is wake up at 6-7am with baby, take care of him all day , he is a very fussy baby and needs constant attention and holding, he will not just sit in his swing or play on his mat at all, try to clean and take care of the house during his naps, try to get ready for work, boyfriend gets home at 4:30, I start work at 5, get off at 11 .. by the time Im able to eat, get ready for bed its already 12:30 by the time i can get in bed. Then baby usually wakes up a few times a night to eat still.. I am so tired but i feel like this is a normal schedule and i shouldn't feel this exhausted... is it normal to always feel so tired or can this be a sign of PPD?