Missing Photos LrC

I uploaded my raw photos into Lightroom about a week ago. For some reason, the last month or so Lightroom keeps telling me that my photos are "missing" when they aren't. The file and photo name are the same and they are located in the right place on my hardrive. 

I've noticed when I look under 'documents' and 'iCloud' where I keep my photos, a lot of the photos have been disappearing. Instead of a photo thumbnail, it has the LR logo and thats all. Under each of these photos is the "cloud" that has to be pressed to try to be downloaded. These are the photos that are "missing" in lightroom. Why were they there in lightroom now gone or "missing"? How do I get them back?

I also notice that trying to find the missing photos triggers regular Lightroom (LR). Not sure why?