Tried getting photos from iPad to iPhone. Clicked on iCloud Photo Library. Ended up deleting most of my pictures in a second. Anybody know anything about this?

When turning on iCloud Photo Library on a device any photos that were placed on the device via syncing from iTunes are deleted from the device. The originals should still be on your computer (if they aren't, they would have been deleted from the device the next time you sync with iTunes). The following link has instructions on how you can add those photos back to your iPad (see the section titled "What if some of my photos are missing after I turn on iCloud Photo Library?": Get help with your iCloud Photo Library - Apple Support

Also note that if the originals are on your iPhone (i.e., if they weren't also synced to the iPhone via iTunes) you can turn on iCloud Photo Library on the phone and they will merge with iCloud Photo Library on iCloud and then to your iPad -- all of the photos on either device (excluding iTunes synced photos) will be on both devices and iCloud.