You can’t be at your best all the time: excellence is expensive to maintain, day in, day out. Working in difficult environment and trying circumstances is mentally draining. Kudos for trying to stick it out but you'll just end up frustrated and distracted, which will affect your work, which will affect your well being.
Learn to recognise when you need recharging, and take a day off. Don’t wait until you’ve reached the end of your tether – that’s when it’s too late.
A day off in the middle of the week when everyone else is working or a long weekend can do wonders for your energy and morale.
You’ve earned those vacation days, give yourself permission to use them when you need them.