H4 denied Form I-539, Application To Extend/Change Nonimmigrant Status

I came to USA on H1B and since i lost job my employer revoked my h1b and applied to H4(As my spouse is also on H1B). He also included my 2 children in that petition. Now i received the denial notice for H4. My children status is still not changed.
I am legal to stay in USA now?
What are the options avaiable to me now?
What about my children?

You start accumulating unauthorized stay from the day your petition is denied.

I would advice consulting a good immigration lawyer to see if you can appeal your case.