Concerned about masturbation

HELP PLEASE ! THIS IS SERIOUS ! Hey , umm so right i am 14 years old and i just recently started masterbating. Like 2-3 weeks ago. i have done it 5 times. The very for time i got "all the way" it felt amazing, and i was kinda hooked on it. the next 2 times was good. but then the last two times it was like..... so-so , kinda bored and plain. and i use hand lotion each and almost every time. its this ok? dose this consider as a Lubricant? i dont know and i'm scared to get any of the lotion in or on the tip of it. the "bell" i guess. I have notice each time less and less semen/sperm comes out, is this normal or ok? and i also have notice ever sense i started masterbating my penis gets thicker and like wider but it losses in length. it use to be long and kinda of skinny but now when i masterbating it is kinda shorter and is hard as a rock and gets fatter! is this normal? also when i do do it, if i dont go slow then really , really fast or if i go really fast then stop "mid-way" the inside turn kinda red and little bit hurts or is stinging . but when i keep going then spill sperm every where it dosnt hurt at all . it feels GREAT! but i hacent been feeling that great feeling in a while so i was thinking about stopping all together cause i see A LOT of things about how it is a good and natural thing but then i see things about how it can hurt you if u do it wrong or go too fast like how i like it. i dont want to go so fast and do it everyday that my penis get really shorter or i rip skin or develop a "foreskin" or anything like that. WHAT SHOULD I DO !!!?? HELP PLEASE!!!