Why do I still feel tired even after sleeping on my day off?

I work as an administrative assistant in hospital for 13 hours a day 4 times a week. We have to complete 48 work hours per person a week. So we have a schedule of 6AM-7PM or 6PM-7AM depends if your morning or night schedule. So after work I walk at least 15-20 minutes to get to bus station to ride on my way home. And I get home at 7:28-7:30 am in the morning and on 8:00-8:30 I get sunlight from sun to get my vitamin d and I sleep at around 10 am because I still eat my breakfast and I wake up at 3pm to get ready because the commute to work is long cuz I only take public jeep. So sometimes I only get 5 hours of sleep before working. And my anxiety is still worse even sometimes I got vitamin d sunlight from sun to treat my anxiety is that because of lack of sleep? Also on my day off even after sleeping for many hours I still feel tired is that because of burnout at work and sleep deficiency? Sometimes on my dayoff I also have bad dreams about my job but when I wake up I just realize its just a dream so its making me more anxious and restless even on day off. So my question is why do I still feel tired even aftee sleeping so many hours on my day off? And why does my anxiety is still there even after getting sunlight vitamin d from sun cuz I heard it can treat anxiety and mood problems is that because of lack of sleep that is giving me more anxiety?
Why do I still feel tired even after sleeping on my day off?
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