Constantly peeing at night, get up 4-5 times. how long should i avoid fluids before bed? should i hold pee in to get used to not going at night?

Overactive bladder: Have a look at this article: http://patient.info/health/overactive-bladder-syndrome It gives general advice but you may need to see your doctor for more specific recommendations for your situation

See below : Having to void frequently at night (aka nocturia) is usually related to either 1) an overproduction of urine at night most commonly related to either increased fluid intake within 3-4 hrs of going to bed or the intake of liquids such as caffeine or alcohol in the evening which stimulate a diuresis, OR 2) to a small capacity bladder (<6-8 oz of urine per void) which may be due to a number of causes