Could you describe what happened in more detail? Like the pattern of events that led you to getting overstressed?

Did your work know in advance you had a Disability? If so, they can't fire you because of it. The only problem is if you formally state that you have a Disability many companies will try to get away with paying you less, not promoting you, and making your life miserable until you want to quit (since firing someone with a known disability because of the disability is difficult). Technically it is illegal to make a disabled person's life hell in a work place, but until the EEOC gets a lot more staff I doubt this problem will change much.

Mental and Physical Disabilities are both protected under the ADA laws, but you have to disclose the disability.

My work place took what I disclosed about my disabilities and the accommodations I needed and used them against me so that my health went downhill fast. However, it did prevent them from firing me for 2 1/2 years after they first expressed a desire to do so. The job went from great with the necessary accomodations under one boss to hell under another boss that was specifically out to make me quit by removing all accommodations and forcing me to work in areas that I couldn't easily physically access without a lot of help (grudgingly given).