recover data from the formatted external hard disk

Do you know external hard disk after formatting data recovery I have an external hard disk and there have been saved a lot of files and folders on it. it is very convenient for me to access data i need no matter where i am and when it is. But there is something unpleasant happen to the external hard disk now. I formatted it by mistake yesterday. What disappoints me is that i have not backup any files which saved on the external hard disk previously. So i lose all of them at present. Those files are important for me indeed, and some of them are my work documents. I want to get that lost data back from but have no idea what should be done. Can you help me?