Take breaks, mental health leave is a sick leave.
Take care of physical health, start by walking at least 5km every day. That's about an hour of walk time, spaced out. Try to get up and move around every 1-2 hours or so.
Give 100%... over a week. It's okay to be more productive on one day and then take it easy the rest of days. Find a rhythm that works best.
Set boundaries, no calls or texts after 6pm. I like to say "sundown is shutdown". 6:01 Friday is Monday's problem (barring extreme circumstances).
Prioritise yourself before the job. Remember you are replaceable in your job, not at home.