Make sure you give your hands enough so that when you land, your horse doesn't pull them out of you hands. Hope this helps 😀
Put two Little Rock's in your hands while riding and try not to drop them. This helped me a lot.
Try engaging your core more. It will help you stick the landing better and therefore be able to hold you reins for the entire jump. Try doing sit ups and stuff to help strengthen your core.
Gloves with grips will help
You could put knots in the reigns
Thanks everyone!! These really help
Maybe you can try to use rubber reins to help you not to loose them, and maybe changing your gloves to new ones (sometimes a good pair of gloves help you to keep the contact with the reins). A few weeks ago I bought ones from @roeckl
and I the difference is huge! :)
Hope it helps!
You are scared so try not to be