Up until i left on maternity leave, my performance reviews were always good. However, since i returned full time, i received a very poor performance review. I feel this is unfair because 1)i was only working half-time for 2 months, 2)my newborn baby has special needs and i used FMLA 3)i have successfully completed a number of tasks and duties. I will admit there were a few things i initially botched but ultimately salvaged. However, since returning i feel that no matter what i do, my boss has written me off as a capable employee. I have not been given the same job responsibilities as before. I am excessively scrutinized. My boss does not include me in key office communication. I fear i will be fired. I don't know what to do.
Before deciding to resign, I would strongly recommend that you consult with an plaintiff's employment attorney licensed to practice in Washington, DC. You may have claims that you could pursue with the D.C. Office of Human Rights, the U.S. Equal Employment Opportunity Commission, and/or the U.S. Department of Labor. You can find such a lawyer through mwela.org's find-a-lawyer search function, or you can contact my firm for a consultation.
You might have 2 causes of action based on the facts that you have described. 1) under Title VII and the Pregnancy Discrimination Act - this for retaliating against you by giving you a poor performance review after the birth of your child and 2) again for retaliation as under the FMLA.
I would not recommend quitting, as the case for "constructive discharge" is relatively tough to prove, and this may jeopardize your case, in the event that you decide to file a Title VII claim against your employer. I would rather the employer fire you, and then proceed from there. Also with the latter you will be able to obtain unemployment insurance, but not when you quit.
Finally note that you have 300 days from the date of discriminatory and retaliatory activities to file a Title VII claim. The information can be found here: http://www.eeoc.gov/employees/charge.cfm
You can contact my office if you need help