What happened to my photos ?

A Few days ago I was having no problems uploading and sharing photos in my "all photos" album. Now, when I click on a picture, there is a white exclamation that pops up in the corner of all my photos as old as 1 week. When I click to edit or share my pictures, a message pops up saying "Cannot Download Photo. There was an error downloading this photo. Please try again later."

I Was having no problems before and even had photos from a year ago. I just recently upgraded my iCloud space from 5 to 20 gb. im worried my photos are lost or corrupted. I'm travelling and have all of my photos on my phone and limited access to informtation. Will this problem resolve itself or is there anything I can do to fix it? Please help!

I Just downloaded drop box and only 400 of 1700 photos uploaded.