What Causes Thin And Watery Sperm While Masturbating?

I am a 36yrs old guy who you'd consider athletic type. my inquiry is this past few days i urinate frequently like for about every 30mins. ,I'm having this sensation that i need to go to urinate(that's all no pain nor burning feeling on my penis) and i've tried to masterbate but my sperm came out thin/watery?
I drink a lot of water(this is already a routine of mine)
Pls. help.
Thanks.