I would recommend discussing it with employment lawyer. If your employer really has not given you any other reasons and your job does not actually require working 100%, then this seems to be a clear case of discrimination. Interestingly, in sexual discrimination cases the burden of proof is reversed and it would be your employer who has to prove that your contract was terminated for some other reason. See also here:
http://www.google.fr/url?sa=t&rct=j&...RHh2YRrFaCnxow