to ask your advice on sensitive issue?

[Wellthisisawkwardnow]

I work somewhere where I have to do key tests every few months - those who fail can be sacked. I failed and was at risk of this, however it was decided that I could stay in job. I am shortly re-taking the assignments.

I was given some health advice (mental health) prior to taking them which included following a certain timetable i.e. not overloading myself. However I have since realised that I will be going against this when I retake in a few weeks - my fault as it was my responsibility to book them, I had been following a different timetable when booking but now think it's too much.

I am wondering whether to flag this and if it would look like an excuse if I do, ie whether I should just stick to it.

Depends on the context. If youre a nurse and tge tests are on calculating drip flow rates for example, if your mh is affecting your ability to do the tests then you arent safe to practice.
If they are non-important just a work exercise, then approach your employer.
Not overloading yourself doesnt mean not doing normal work commitments necessarily, it is too ambiguous. Who gave you the advice and for what mg condition as this may help people advise you x

They are important as they are academic tests. A workplace health practitioner gave me the the advice, it was actually quite specific i.e. don't do two tests within 24 hours. I booked according to the old timetable however am aware that I will be doing both within 24 hours now. Really this was something I should have checked before. The solution is that one can be moved to a later session but I'm wary about asking for this and how it will sound?

In which case you need to do them but have grounds to request they are spaced further apart.
Asking for this sounds proactive and will be looked at favourably.