To learn you will have to deal with the uneasy feeling. Everybody's way of dealing with hang-ups like this is different. The problem is we are still near enough Mk I cavemen designed for living on the surface at 1g. The rational thing is to accept the aircraft you flew in is older than you and it's still in one piece. But fear of flying is not a rational thing.
If you decide to continue you must trust your instructor. Totally and absolutely. You will not be put in a position where you will come to harm and you will have to learn to accept the bumps and gusts that will come your way. Have your lap strap fastened firmly and your shoulder straps with a similar tension to that in a car. Sit so that your arms and legs are almost floppy and go with the flow. When you are not flying have your hands on your lap and don't grab anything except for your hands if it gets bumpy. Hanging on to your seat, the door or any handle will do you no good. It won't stop the bumps and you are not strong enough to hold yourself in position. That is the job of the lapstrap.
The quicker you learn to deal with bumps, the quicker you'll learn and the better the pilot you will be. Here is a
girl dealing with bumps.
PM