Mental harrasment by superior

I am working with reputed MNC from 6months,my performance was going good all the months. Suddenly due to health issues i couldnt perform well in may and june, as per norms i will be put in to observation for 6weeks where i have to clear proving myself if not i will be subject to termination also i have to sign the same letter. Till april i was the top performer,they use to be nice with me. Suddenly as my supervisor dont like my attitude he made me to sign the observation letter. I asked him so many times to give at least two weeks times which he denied. Also changing my shift with out prior information. I asked him to keep the papers in hold to discuss further, as i signed i was told that it cant happen. I was in shock wen i asked to sign with out thinking i signed of. I feel ill and mentally im sick to go to office and work he doesnt even have courtesy towards female employee. I didnt proceed internally for giving complaint. I want to proceed now. If at all i didnt get proper justice, through law what can i do towards discrimination.