You need to consult with an employment attorney. Depending upon the degree of your depression, you could be protected under the Americans with Disabilities Act.
You may be covered under the Family and Medical Leave Act (FMLA), and you may have rights under the Americans with Disabilities Act. You may want to file a charge against your employer with the Montgomery County Human Rights Commission. Under Maryland law, your employer bears the burden of demonstrating that you quit or were terminated for gross misconduct. Did you try to go back and then they terminated you based on your "state of mind"?? I cannot answer this question, as posed, but you should contact an employment attorney for assistance.