What are my rights if I had to quit my job because my employer wouldn’t accommodate my disability?

You may have claim for failure to make a reasonable accommodation and/or for disabilty-related discrimination. There are a couple of prerequisites to having a claim:

1) The "disability" must be medically verifiable and must be something that reasonably affects basic life functioning. If the employer asked for some proof of a non-obvious disability, you'd have had to provide it--the employer does not need to simply take your word for it.

2) The accommodation must be "reasonable," which means:

a) It must be not too expensive or too disruptive to work;

b) It must let you do the job for which you were hired/being employed in--the employer does not need to transfer you to a different job or create a new job for you;

c) You must be able to work the full set of hours--the employer does not need to cut back your hours.

Examples or reasonable accomodations include getting a stool for a cashier who normally stands, if she has leg/feet/back problems, so she can sit; letting someone with irritable bowel syndrome take more frequent bathroom breaks, or letting a diabetic take snack breaks to balance blood suger; giving a hearing impaired employee a phone with better amplification or software that displays voice mail as text.

Things that are not reasonable accommodations include letting someone who does not have stamina and who was hired for a full-time position work part time; letting someone work from home when they were hired to work on-site; transferring a warehouse employee to a desk/office job; etc.

If you believe that this was a failure to make a reasonable accommodation for a medically verifiable disability, then either speak with an employment law attorney about  your rights and a possible lawsuit, or contact either the federal EEOC or your state equal/civil rights agency about filing a complaint or claim.