Forcing to resign when pregnant - got my signature forcefully on PIP and increased my monthly target

I joined my company on 4th Jun 2018 and i conceived in July 2018.. I informed my company verbally about the same to change my process, as i am in a sales department and got lot of pressure..now my company is forcing me to resign and got my signature forcefully on PIP (performance Improvement Plan) and increased my monthly target..due to which i am getting lot of tention to save my job..they denied to change my process as well..
What shall i do in this condition?? Can they fire or terminate me on my performance basis..
they metaly tourchering me..I can not survive without job..
Please advise the solution to fight with them..

Congratulations, lady. Its a challenging situation. Only a humane/ kind hearted manager will handle well. Please talk to your manager and convince them.

""Please advise the solution to fight with them"
Fight will get you no where.
You need to convince them as member above has written.
What industry are you working?
The company knew about pregnancy when you joined and still they are giving you higher targets.
Try and keep options out for another job as you are in tough situation with small child and tough targets.