ZW: nice video, looks like it was taken on a cell phone. Maybe next time try landscape (sideways) instead of portrait.
Have you considered trying to improve your distance per stroke (DPS)? I count over 50 strokes and about 48-50 seconds for a 50 meter pool length. Lots of activity for little forward progress. What could improve your DPS?
1. More horizontal in the water. Most of your back shows above the water. Lower head would help. Less pushing down on the water with your hands. Keep the palm of your hand facing the back wall as far in front as possible and as long as possible.
2. Arms cross over the center in front of the head. During recovery keep your elbows high and outside your body line then extend the arm straight out from the shoulder WITHOUT straining. This is hard to fix by yourself so have your compatriot watch you until you get it right. Best of luck. mjm