how can i refresh my photo stream on my MacBook pro?

ive always had my photo stream on all my devices and my photo library on my MacBook seems to update/ sync whenever it wants i.e. not as soon as there is a new addition to my photo stream.

it updates on my iPad but not on my mac. I've tried quitting and relaunching and force quitting the photos app from the activity monitor. any help?

im on macOS high sierra v.10.13.4

thank you!