Change of custody

Can someone tell me how hard it would be for my ex to change our son's custody from mine to his?

Our son is 2 years old, has been living with me the entire time since his father left us back in August 2005. His father does only the visitation ordered by the state but does no extra time. He doesn't provide basic care for him when he does have him, he sent me an email regarding our son having blood in his diaper, but did not come get his medicine for constipation or seek medical attention....

We have had heated exchanges, and I have sent a few nasty emails to him regarding his friends, but nothing about him or anything. I have never been arrested, or gotten in trouble for anything what so ever, but my ex has been arrested for drunk driving.

We had to sell our marital home, which resulted with me living with my brother's 80 miles away and quitting my job. I am awaiting permission to move out of state to live with my parents and go back to school. I won the first round, now I am just waiting on the appeal.

Can he take my son away from me because of some angry emails or comments made regarding his friends? Is that really strong enough to take my son??

I'm really freaking out here....thanks in advance

If the child was not exposed to the nastiness, the court probably won't consider it in relation to the custody issues. But consider being on your best behavior until the litigation is resolved.