Why does Apple keep sending me notifications regarding My Photo Stream? Do I have my photo stream? Or they just send this out generically to everybody. I don't want to lose any photos. But I can't find my photo stream anywher

They send those notifications to everyone who has an Apple ID in case they use My Photo Stream.

On your Mac. open your System Photos Library (your primary library), go to Photos' iCloud settings pane and see if you have My Photo Stream enabled:

If it is just uncheck it. If you read the text with the My Photo Stream checkbox you'll see that phoitos from other devices are automatically imported into your library.

On mobile devices go to the Settings/Apple ID/Photos setting pane and check to see if you have MPS enabled.

If it is enabled you'll need to select those Photos from other devices and save to the library on the mobile device.

If you don't have MPS enabled on any device just ignore the notifications from Apple.