Fluids and actual weight?

Hi so I drink a lot of fluids mainly water or mios , I would say about 20 bottles a day, and I eat a lot of sodium. I have been trying to maintain but I can't tell if I am because I have been drinking more because I feel thirsty all the time. Over the last month I have dropped a pound and now am 4 lbs over what I was when trying to maintain I was eating 1200 calories a day and now I am eating 1400, could I be gaining a pound a week with just 200 over? Or is this all water plus sodium?