BEnGillam solution worked for me,
apperantly the problem was that i had many photos and videos from iCloud in my iphoto app and they did not download to my ipad and even there were no thumbnails for them (so i saw allot of gray icons instead of photos),
the app was occupied by downloading these thumbnails, i saw a little round wheel next to the upper left corner of the screen indicating network activity by the iphoto app, when i closed the app (minimized it), the activity stopped, so i went to imovie as BenGillam suggested and scrolled through all the videos there, that caused the app to download all the video thumbnails, later i scrolled through my pages of photos and waited for them to display thumbnails,
after that there was no round circle / wheel and then the share successfully worked,
that saied - the icloud share is so slow, dont bother sharing more then 4-6 photos at a time