Don't WTFU…
I came back from Holiday with a Gastric Flu bug, wiped me out for a few days. Tried to MTFU coming out of it and ended up with Viral induced Pericarditis and Myocarditis – basically swelling and inflammation around the heart presenting itself with heart attack like symptoms and responsible for 20% of sudden death cases in young people – epic!
One ambulance ride, more xrays/ECGs/scans than I can remember, a few nights in hospital, a lot of powerful pain killers, 2 weeks stuck at home later – I'm only just almost better. I'm only 27 and never been ill in my life.
So yeah, WTFU might not be the best approach if you're body is crying out for a break!