This might not be right but could it be that you're drinking too late at night. I tend to stop before 8pm most nights and ensure I empty before going to bed. Also you will be wearing a pad all the time that should absorb some, it's surprising you're needing to go 3 times a night.
As for the spasms I recall it happening a few times to my bladder. Not many though and not the bowel. I think I'd look at my diet and the time of eating. You might need advice on that. I'd see if that has any effect although as said above you could ring a specialist nurse at the hospital or even at PCUK.
Normally things settle after a month or two although pads may be needed for 6 months. All the best Peter