database 10x’d in size in one month

I have a website with only a few posts, a few comments, and a few images (all somewhat small) and in 5 weeks my website has grown from 400MB to 9GB, files are 4.2GB and the database is 4.5GB. I can’t find where this came from. Any ideas? Is there a way to do a search on the database or file structure to find large items?