You definitely need a bigger board. Judging by your height and weight the board should reach your belly button and should have a nice thickness to it. You should go for a board that is rated for 200 lbs to 220 lbs. It will help you float better and paddle easier. Also you may want to move up your position on the board, arch you back and raise you legs out the water. You may be creating drag by not positioning yourself correctly on the board.
You need a longer board. Judging by your video, you were dropped on your head as a child or a crack baby. You should go for a board thats about 6'2" and try standing up. Stop blaming your board for not knowing how to ride barrels. Pea's out nucca