Wife wants to leave the state with my kids

I'm a 22 year old male and married with a three year old and a one year old.

My Wife recently asked me to leave because of the numerous arguments we have had in the last two months. She asked for a separation so instead of her leaving I let her and the kids stay in our apartment. I went to live with my parents.

I asked her to get counseling she agreed and after I went into my boss's office and asked for the papers for the company's mental health care counselor I took them home and she threw them in the garbage and say no never mind its over!

She is now wanting full custody of the kids and to move them to another state. I'm so stressed out I don't know what to do. I need and want desperately to be in my children's lives. What are my options and what are the laws in taking Children out of state?