It looks like your stirrups are to long, your feet have been pushed to far into the stirrup because of it I think.
You are probably leaning foward to try and keep your horse going, try sitting up and not pushing that much with your body so much, I did that as well sitting up actually made it easier.
It will get easier once your horse is more willing to canter :)
I have to fight my horse to stop now lol
Your horse looks like he might be on the wrong leg in some... not to sure though, your reins are a tad long but shouldn't really matter you want forward and if he's a good horse and wont run off that's fine.
Not really the best critquer but hope it helped