Why am I being laid off my job for being pregnant?

I worked at a privately owned retail store owned by Koreans. I went on Vacation for 2 weeks and my manager was fine with it. I came back and she asked, "When are you ready for work?" I told her as soon as possible before I told her I was pregnant. She said it was okay, and that it was my life and she couldn't say anything. One week went by so I called and she said she was going to have her son working and she'll call me later. I also still have the key to the store? The problem IS, I worked illegally for about 3-4 months when I kept asking to be added to payroll. I signed all the documents but she kept paying me cash. Eventually in the last month she added me on. Now I believe I'm being laid off.. and if so I cannot prove that I've worked past my probation period..other than a police incident while I was working and the store got robbed. I'm very upset I'm not working because my baby's Dad isn't either because he's also off for Summer vacation. None of us work and it's bothering me because I've always worked. I had another job because it was full time and my babies dad insisted I kept my part time only so I quit my first day. My question is.. what can I do? I think she is gong to fire me and is it right to lay me off for such a duration? What if she cuts my hours?