I will try eating more salt and see what hapless, I have been having some in the morning, some with food and some before playing. ThanksYou are probably are not getting enough sodium. This is the issue that comes up in people who start to eat better. Natural whole foods are all low sodium. This is why 50 year olds seem to have more endurance than you. Its not endurance. Its just you don't get enough sodium so your muscles can't do what you want them to do.
Most people eat a lot of processed foods which are all high in sodium. This is why stopping coffee helped, because caffeine increase sodium excretion through kidneys even more. Problem is if you do endurance sports of any kind, you will notice the hyponatremia more because your muscles need to contract hundreds of times over hours.
Without enough sodium, you will not be able to contract muscles properly because sodium is needed to send signals from the brain to the muscles to contract. Also your muscles will swell because they will fill with fluid as the fluid in your blood will be attracted to the salt inside your cells, instead of staying outside your cells in the blood where it should be.
You may be shaking salt on your food every meal but thats probably not enough. You need to get way more sodium especially for endurance sports where you are active for a long time and you need even more if your sweating a lot on top of it. The large muscles in the leg suffer the most because they need the most signal to contract because of their size. Also you shouldn't be using eggshell powder at all since you drink 3 cups of milk a day. That is more than enough calcium, eggshell is pointless. You need way more salt, you can try eating pickles with your meals, and even gatorade while you are playing. And you should try to add more salt in the food you cook. It will not affect the taste as much when you add salt when cooking.