Two different issues here:1) Being on probation does NOT prevent the company from terminating you, and does NOT mean you are guaranteed pay for the whole 90 day period, unless and only if you had an actual written contract which by its plain terms stated you could not be terminated during the probationary period and/or that you would be paid for 90 days no matter what. In the absence of a contract, you could be terminated at any time, for any reason, even during probation, and would only be paid for the days you worked.2) However, the above said, an employer cannot terminate somone for having a medical condition (e.g. cancer) or needing medical treatment. Doing so may be considered illegal disability (i.e. medical condition) related employment discrimination. There is reason to beieve, based on what you write, that you may hae been let go due to your medical condition; that being the case, you should contact the federal EEOC to look into filing a discrimination claim. Good luck.