Do you take any meds? I'm curious, because I have adult ADD, and I take Adderall for it. One of the potential side effects is an increased sex drive. Which is interesting, because on the other hand, it can also DECREASE your sex drive (which it does for me, I can't even get hard on my meds unless I really work at it)
But 16 times is A LOT for one day. I think the most I've ever done in a day is 5 or 6, and that was the early puberty days when the fascination with boobies began :3
16 can't be healthy though... I imagine you're pretty sore XD
All jokes aside, if it's something you're doing to deal with emotional pain, I would suggest seeing a therapist. "Therapist" is a word that makes most people cringe, but they aren't all bad, and there's no shame in wanting to fix yourself and your problems. Also, do you exercise regularly? I ask because doing so could help a lot. Having an orgasm releases chemicals in your brain that can make you feel content or happy, and just relaxed in general. Exercise releases those same chemicals! I know that for me, I feel so much better throughout the day if I start off with simple work out. I'm talking like, 30 pushups, some crunches, jump rope or jumping jacks, and then a short walk around the neighborhood. Takes an hour out of my day at most. And then I usually masturbate once before I go to bed, it feels more rewarding at the end of the day, pluss it helps me sleep.
If it's something you're doing to deal with boredom, and just to kill some time, I'd suggest a hobby ;P
Sorry this is a bit lengthy, but I hope it helps you some! Out of everything I said, I think you should try some exercise... at least an hour every day. Good luck, and try to keep your hand off of your dick