Difficulty with Photos

I have a MacBook Air. When I downloaded macOS High Sierra, iPhoto seemed to disappear from my computer and be replaced by Photos. When I try to open "Photos", I receive the message, "The library 'Photos Library' has inconsistencies that must be repaired. I click on "repair" and then I receive the message, "The library could not be recognized." I don't know what's happening. In the past, I was accustomed to taking photos on my iPhone, and they would seamlessly appear in iPhoto on my computer and all was well. Can someone help with this? Thanks!