Maternity benefits in Notice period - Can i sue my employer for pressuring me to resign?

Hi, I have been worked with a company with 3.5 yrs, now, a few days ago, my boss mailed me that i m not doing good at work and mailed me that my performance is not good.. Based on that HR called me and said that we are terminating you that your performance is not going good, then i told my HR that I'm pregnant (4th month) i can't leave the job. But they pressurised me to resign immediately and i have resigned that day only asking for one month notice period. Can i sue my employer for pressuring me to resign and can i avail maternity benefits now.. I am on notice period.

This is done to avoid payment of maternity benefits.
You need to put up the matter of pregnancy to the company in writing.
Are you covered by ESIC?
Inform the company that I do not want to quit and your previous resignation was under pressure.
If still they do not relent, go the Labour officer of the area and complain regarding your problem.
There are statutory rights granted as welfare entitlement to women employees and employers who try to deny them can be taken to task by concerned govt agencies.