Pro,

"And about the physical activity tolerance - if I push too hard and my symptoms return, isn't that a sign of new brain damage that I caused to myself? And even if I, by accident, push hard enough to cause my symptoms to return, it'll only delay my recovery, but not cause any further brain damage? I'm worried that it won't only delay my recovery, but also cause more brain damage (the field trip that involves physical activity and hiking). And if it doesn't cause new brain damage, what is the reason to the return of the symptoms after heavy physical activity? The delayed recovery sounds like it carries more risks with it (I hope not)."

Physical activity that causes a return of symptoms means your brain is still recovering. Your brain can be in an extended 'still recovering' condition even if you are symptoms free during low stress times. The injured brain will forever be sensitive to stress. The more and better it heals, the more it will be able to tolerate stress.

The brain needs to re-establish its mechanism for self-regulation. Without self-regulation, symptoms will manifest. You need to slowly work on helping your brain re-establish its ability to self regulate. If you choose not to try to help it re-establish this ability to self-regulate, you should not go on this trip. A return of symptoms can result in loss of skills/functions that keep you safe. A lack of balance, motor control, etc. could increase the risk of you falling and further injuring yourself.

Since it is apparent that you do not listen well and take an extreme effort to convince, your ability to make wise decisions while on this trip is questionable.