Theres lots of good advice. IMHO, a balanced routine is no.1 then stepping back and asking for help.
all work and no play... a good routine includes enough sleep/rest, balanced diet/multivitamins and excercise/play/social contact. caffeine and alcohol can help, but too much is never a good plan - moderation in all things is sage advice.
break up problem into small easily achievable units of work.
take a step back, do some housekeeping tasks, change tunes or have a refreshment.
perhaps you cant see the wood for the trees? ask for help or discuss with mentors/friends, even pair up or admit defeat and swap tasks.
go for lunch or call it a day, hopefully when you will come back energised. sanity is more important than a crappy stressful job.
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