Think I'm in need of some reassurance.

hazedot

Hey there guys,
I'm currently in training for a 50 mile cycle ride and although I've been eating well and cycling for almost 2-3 hours a day for a few daysa week I'm gaining weight. Could this be because my body is retaining water to repair my muscles?
This is my thought as I can't think what else it might be. Does anyone else have any other suggestions? I'm certainly feeling stronger anyway and my clothes are all pretty much falling off me, so do you think I'm right about the water retention? Oh and it's also my TOM so that might not be helping either!
Since August I've gone from weighing 244lbs down to 195-199lbs. Could it perhaps be a plateau?
Thanks in advance for your help
Hazel