My work was gone when i open illustrator in my ipad

I was drawing for about a whole day and a half then when i came back to check on everything i found all my work is gone completely. I really worked hard to get this done and i dont wanna start again, can anyone please help me get it back? Oh and by the way i did save my work before i left it but when i came back to check on it it was gone!!!!!!!! Please help