Can I get my dog back? Please help me?

I live in Waco Texas & my dog is a Shetland Sheepdog. We bought her from the newspaper from a private owner when she was 6 weeks old. Some kids from across the street came over & were playing in my yard without asking me if they could come over and neither of their parents were watching them; the youngest kid was swinging on the swing & my Sheltie loves chasing the swing. While she was chasing the swing she accidentally nipped or scratched (we aren't sure which as we never saw it & their story changed) her leg. Animal control came to my home later that evening & I signed the paper for owner surrender & she went to the humane society. I was in shock & also have been battling the flu with a high fever & I have been taking Benadryl and Dramamine every 4hrs, so I was pretty out of it when the officer came to my home. My dog would have to have been quarentined for 10days anyway but with the shock of the situation & being sick I honestly didn't know clearly what I was doing. I had already filled in the basic info & signed the document & wasn't told til after I handed the paper to the Animal Control Officer that I couldn't get her back. I'm willing to pay boarding fees & I didn't adopt her from a shelter I bought her privately. I had her spayed, shes been on heartworm prevention & I have always taken good care of her. She wasn't being aggressive & it was an accident. Also, my other sheltie has never been with out her & he now refuses to eat, he barely drinks and just lays around. He is completely lost without her and so am I and my children. Is it possible for me to get her back even though I signed the paperwork? I wasn't in the right state of mind & was sick with a fever & a little dehydrated. I feel it was somewhat unfair for me to have to make that decision right then when I was in shock, scared & sick. I was worried about possibly getting kicked out of our home because we are 1500 miles away from any family and have nowhere to go. If we lose our home we rent, we will be homeless. This just happened on the 9th and its now the 12th and now that I have broken my fever & am not taking so much medication, I realize what I did. I hardly even remember filling out the paperwork & barely remember talking to the officer. Can I get my dog back? Is it a possibility? I love her with all of my heart and my family and I want her back. PLEASE HELP ME WITH ANY ADVICE AS TO HOW I SHOULD HANDLE THIS AND WHAT I CAN DO.