Hi - you've gotten some good advice here... did you talk to your principal yet? As mentioned - your co-workers dont need to know - BUT - you need to get this officially presented to HR - that you do need accomodations (they will ask for MD notes for sure).... not only does this let them know that you truly have health issues - but "protects" you, as mentioned, from a potential termination due to your health (once presented must be taken into consideration and you have handed the liability to the employer who will be much more hesitant to take any adverse action against you).

Reasonable accomodations unforutnately are often left to interpretation of the employer and a point of dissention - but with the large employee base like it sounds you are working with - reassignment to a part time position sounds like it would be feasible for them if necessary. At least presenting this officilly will ensure you can protect yourself! If you do at some point need to go on disablity - does your employer have a plan too? This is usually quicker to get - but if you are terminated before you can file a claim then its useless....

SSDI of course is another animal - you would probabably be required to get both.

Wish you the best here - unfortunatey coming from a backgorund in HR - I saw employees ending up being terminated because they did not come to us with their issues - and many companies are unethical enough to cut their losses even though they may know you are sick - because it hasnt been presented to them formally...... however, once they are notified of your medical issues - they must tread very carefully.

Hang in there