Lost over 60 gb of free hd space overnight

I haven't downloaded anything recently or viewed any suspcious sites or even any xxx sites, however for some unexplicable reason, overnight, i've lost 60 gb of data, and watched the last 10gb fly out in less than 5 minutes. I now currently am running on 105 mb with 324gb in use. the 150gb in boot camp seem to be unnefected, but i haven't used BC in months. before that even happened, i was told my start up disk was full when i had 60gb left, when this whole thing started. Looking at my processes i had dozens of multiple dashboard clients and one other i can't remember that had 30-40 iterations of it. a restart solved some problems but it still says i have 105mb remaining. trying ot feverishly back up my data, though the data itself looks pretty stable and the disk is in great shape. the only problem i have is the missing 60gb. Please help me apple community.