It sounds like a bad sign. Stop doing any partitioning work, and try to use the disk as few as possible.
As others have pointed out, it's better to perform a backup of your data first, and then trying to discover what happened to the hard drive.
After you have managed to secure your data, if you want to diagnose what happened to the disk, you could use a S.M.A.R.T. tool to see if it has some physical damage; I would suggest you Palimpsest (also called "Palimpsest Disk Utility" or "Gnome Disks").
S.M.A.R.T. tools can be used in two ways, the first one is to simply retrieve disk attributes, displayed in the form of an ID, a description and a value, that can help to understand the health status uf the disk; to understand the meaning of these values, you can refer to this wikipedia article.
The second way is to run so called "Self tests", there are different types but all of them perform some read/write activity, so if the disk is already damaged, they can potentially worsen the situation; anyway, in less critical situations, these are useful for an in-depth diagnosis.
Regarding the backup of the data present on the disk, besides manually copying your files, you can also consider to clone your partitions to another (healthy) hard drive, to maintain not just your data but also everything else (operating system, settings, and so on). A very handy tool for the task is Clonezilla.
I suggest you to grab a copy of Parted Magic, it is a Linux distribution tailored specifically for these kind of tasks, it can be booted from an USB pendrive and contains all the aforementioned tools (and many more useful ones).
For future reference, keep in mind that all the work on partitions should be done after a backup and with a Live system. Also, a periodic check of the health status of the disk can prevent the discovery of possible errors when it is too late.
If you need more help with the above tools, feel free to ask.