Have you tried it on your computer since then?
Not all hard drive would be seriously damaged for dropping or shocking.
So, simply connect it to your computer and check whether there is a problem by running Chkdsk like this:
Right Click you drive in My Computer > Properties > Tools > Check Now > Mark “Automatically fix file system errors" and "Scan for and attempt recovery of bad sectors".
If this drive could not be read functionally, such as receiving some error message, you'd better format this drive to see whether it could be fixed. All right! Do you have a backup of everything important? If not, you'd better restore your all your important data at first and then format it latter.
Check more information of data recovery freeware here:
blog4mark.blogspot.com/2012/11/how-to-repair-corrupted-pen-drive.html
If this drive could not be read completely, you may get some physical problems, you'd better ask an expert for help, if the inner data is really important.