I'VE LOST GIZMO!!!!

I put him out this morning and as i always do, taped him (round his belly) to his little lead so i can always find him and he was out there from 11-3 and my mum saw him at 3 but when i went out there about 3.30 he was not in he lead and ive ripped the garden up so there is no where really he could be hiding. he could have gotten into the other next door neighbors gardens but i knocked and asked and they looked and cant find him. he could have gotten out the path down the side of our house but i dont know how far he would go. i miss him already. i cant find him anywhere. it probably sounds crazy but hes sooo important to me and now i dont have him anymore. if it get too cold out there he will die because hes a trpical tortoise and needs high temperatures. i dont trust the people in my area not to have taken him and not give him back.
i'm so depressed