Edit1: some thoughts based on comments. I was diagnosed with low vitamin D a few months ago but took bills. Maybe a month ago I ran out. I thought getting outside more recently was enough. You all inspired me to be more serious about it. Got my vitamin D3 and b12 pills.

Also, I noticed the two days I felt so tired I slept later and had alcohol too late in the night. One drink but around 12am. I think not just sleep quantity but when I sleep and quality matter.

Will aim to take my pills, not drink after 8-9pm if I drink, and sleep before 11pm.

Thanks for all the advice :)