Lightroom not saving edits

I really need some help bad. I have edited over a 1000 images in the last 2 days using Lightroom. I went back through them to lighten and darken some of the images. When I close Lightroom and turn my computer off, come back the next day and open the image my adjustments are not saved. I and also see a major difference when I leave the Develop module and go back to the library module. I am really worried since I am working on wedding images from Saturday.