I masturbate daily and I sometimes end up doing it 4 times a day , or 5? I stop counting when I am too horny.I also eat well so I won't ejaculate my sources of energy.
I consider masturbating as any other activity, it needs energy and effort.
Of course you feel tired , it's so mentally consuming to concentrate and make up images or remember the slightest detail of my best sex date.People above asking about sex dates if it qualify as masturbation , I think it's more physically if you are a stud ofcourse and mentally consuming so ofcourse you are gonna be tired.