Im pretty sure the main reason I got fired was for being pregnant. Do I have a case? please read details.?

I worked at a clothing store on melrose in which I did everything from sales to opening and closing the store. I never had any problems and everything seemed fine. On my 9th month of working there I found out I was pregnant. One day before I had told my boss I was pregnant I had some complications in which I was bleeding and really dizzy, so I called my coworker to come cover for me and as I was waiting for her to come I called my boyfriend to go pick me up and looked up the directions to the hospital. While I was doing this a man went into the store to stole stuff but I was not aware of it until my boss told me the next. This day I told my boss why I was distracted because he wanted to fire me. He did not fire me but since that day he kept telling me that business was not well and that he might be closing the store. A few months later there was another shoplift incident in which I was aware of and I did confront the person and called the police (I have the report). Next day the owner had a meeting with me in which he told me that I should of snatch the clothes away from the shoplifter or ran after her to stop her I was three months pregnant when this happened he also told me that it did not seem like I could handle the job because I couldn't get physical with a shoplifter. He really wanted to fire me but he knew it would have been unfair so he didn't. One month passed and in the beginning of December 2010 he told me that he had to let me go in 2 weeks because the store was not doing well and he was going to close it. I got laid off at 1 year of working there. In Late January I filled for unemployment because no one was hiring me. When the owner from the clothing store was contacted by the unemployment department he called me and offered me a job at the offices from the factory in which the clothes from the store we sold was made and I said sure so I closed my unemployment case. I have not been able to reach him since and today I passed by the store which is still open ( I was told it was going to close and that he couldn't afford to pay me anymore) and it had a big help wanted sign.