App Store wont upgrade my Yosemite

Im on OS X Yosemite version 10.10.3, macbook pro w/ retina mid 2012.

Its hard for me to explain so I took screenshots . Heres what it looks like. It stays spinning on the "Checking for updates" part. And when I hit Update it won't do anything.

If I close it and reopen, it looks like this

Does this happen to anybody else?