i cant poop – drink

Drink water — I keep reading nonsense of drinking 8+ glasses of water, sure if your 9 feet and 300lbs than maybe.  Yes be hydrated but on liquids….that idea that you need to drink a huge amount of water are based on studies from the 60’s I believe.  Drink moderately, I say 1L is plenty if you drink other liquids.  Water is best but staying hydrated makes the stool softer.

too much fiber?

Yes, it is possible to have too much fiber in your diet.  If you are taking supplements or things high in fiber.  Don’t go overboard with it, eat normally.  Supplement as a last result.  You will be better off…

how much fiber?

I have done lots of research and the magic number seems at 20g a day. However, depending on your weight it is lower or higher but this number is average.