Q: Why is my main disk replaced with an EFI boot disk?

So I have three partitions on my MacBookPro. One labeled Main which has Mavericks on it, and one labeled Windows which has Windows 7 on it. The third is a recovery disk. Anyways, a few days ago I forced my mac to shut down using the power button out of Windows. Then when I went to boot into my Mavericks partition, it showed the apple symbol on a white background like normal. Then the little swirly loading thing (sorry I have no clue what that thing is called) appeared like normal, but then a loading bar also appeared underneath the swirly thing. Well I didn't know what was going on so I force shut that down and rebooted into Windows. Today I tried to reboot into my main disk again. This time I waited for the bar to load all the way. But when it finished loading it just shut down the computer. I held the option key at startup to see my boot options but instead of seeing my main disk like before, it had been replaced with/renamed EFI Boot. When I select that disk it does the same process with the apple logo and the loading bar only to shut down again. This really makes me upset because all the stuff on my main disk is very very important. Oh also I will mention that I can still see my main disk and all of its contents through my windows partition, and may be able to copy it, but I would prefer not to have to reinstall Mavericks because I don't know if I'll be able to re-download Logic Pro 9 and I don't want to upgrade to Logic X for 200 bucks at this point. Help. Oh and no I don't have a backup disk.