This answer aims to add to, rather than replace, those which have already been posted. I also wish to distance my comments from issues of mask-wearing and COVID. I acknowledge they are realities of your current situation, but I think there's value in discussing your question in the context of a return to relative normality.
Exhaustion is technically an absolute condition, so it can be useful to employ the word 'fatigue' instead.
We tend to measure exhaustion against the most fatigue we've ever experienced. When we think about exhaustion, it is natural to remember the occasion upon which we have been most tired (for example, in the final stages of a first half-marathon), and find it difficult to conceive of being able to function in an even slightly more fatigued state.
But, as is routinely demonstrated to military recruits, we rarely push ourselves to the extremes to which we are capable. The hurdle is largely psychological. When an activity is voluntary (such as the half-marathon), we find ourselves continually at war with the knowledge that there is nothing compelling us to continue.
Military training, on the other hand, assumes the responsibility of preparing soldiers for circumstances in which any decision to quit will likely result in permanent injury, imprisonment, torture and/or death.
If you speak to anyone who has had the good/bad fortune to experience such training, they will likely relate an incredulity at just how far they were able to push themselves.
So, whilst I mean in no way to diminish your efforts thus far, or to assume you have not pushed yourself to a similar degree, it is quite possible that - despite your experience of relative exhaustion - you have not come close to your limits.
Please however heed this warning. I am not posting this with the intent of motivating you to push yourself to ridiculous levels. Exertion of this sort must only ever be done with the full knowledge of a well-trained supervisor or team of supervisors. It comes with a range of risks, including a much higher likelihood of injury, reinforcement of poor technique, possible heart failure and dangerous levels of dehydration.
It is not wise to push yourself to such an extent on a regular basis. Such effort is actually deleterious to the body and requires far greater than normal recovery time. The purpose of occasional maximal efforts is to educate you as to how far you might push yourself should you ever need to.
Even elite fighters (at least those with experienced trainers) during a fight preparation phase rarely push themselves this far with any regularity. Like all forms of training, aerobic and muscular endurance training is best achieved via gradual progression with scheduled 'deloading' phases, so that the body adapts safely to the increasing demands to which you are subjecting it.
If your teacher is routinely pushing you to levels at which you are experiencing a significant loss of co-ordination, mental acuity, and body water content, and at which you are experiencing nausea and dizziness, I suspect you may be pushed (or you are pushing yourself) too far, too often.