Is it possible to move deviations from one page to another in my gallery?

Yes it is. To do this you will need to select the deviation or deviations you wish to move by clicking once on the deviation thumbnail. To select multiple deviations you can ctrl+click (command+click on a mac) on the thumbnails to select them individually or click in the empty space next to a thumbnail and drag a selection over the thumbnails you want to select. Once selected you can drag that deviation (or those deviations) to the bottom of the page and then drag them to the page number on the pagination feature at the bottom of the page before the comments area. When you release the mouse these deviations will be relocated to that page.