Basically your body always recharges your sperm amount (up to a max, which is different for each guy), and then the sperm must be ejected either by masturbation or night discharge (wet dream) because sperm dies pretty fast, and you're body doesn't need dead useless sperm inside it.

I jerk off once a day before I sleep, If I don't, I can't sleep. Also If I do it during the day I find I get really drowsy for the rest of the day.

If you find you're producing an extreme amount of ejaculate go to the doctor one of your glands may be overreacint or infected. I find I produce a lot more than other guys (pretty much on a peter north level) but when you actually try to measure that in a cup, it still doesn't seem that amazing.