I would hope any newish pilot reading this thread can take on board the following:
If you are genuinely fatigued & you consider the fatigue (level) enough to affect the safety of the operation. Pull the pin & report UNFIT.
It may inconvenience the airline, the passengers & the schedule, but you'll survive (health or employment wise) to fly another day.
Schedules & commercial pressure will back you into the corner, however your the last line of defence in the swiss cheese model from an accident.
click.