I am wondering if it is like either of these two videos because I am having the same problem:
It happened today and I am trying to figure out my options as a couple of ppl make it look like all is lost. I'm optimistic that this is not totally true. I would advise doing your homework and not rushing to try as many home remedies as you can find because not all would apply to your problem. The more you try that are wrong, the harder it will be to recover data.