Broken Fibula

I fell down the stairs and broke my fibula 10 days ago. I've still been weighing myself daily with a leg cast on. My weight has been almost stagnant since the injury happened though. I'm only down one pound.

My question is, could the pain and swelling be causing me retain weight?
I went from 1200 calories a day & walking 12,000 steps a day to 900-1000 calories & completely sedentary. I'm so worried that I won't keep losing while I'm laid up for several months

Edit: I had gastric bypass surgery in 2003. I lost over 100 lbs & kept it off eating far less than 1200 calories per day for 10 years. I gained all of the weight back plus more though, from poor food choices but mostly through liquid calories. I've been sober now for more than 3 years & am now trying to get this weight back off without surgery this time. My bariatric doctor says I should be having 900-1000 calories a day, I can go up to 1200 with exercise.

Also, although I'd love to not worry about losing weight and concentrate on healing now, I don't have that luxury. I have a severe ventral hernia that requires surgery. It is currently scheduled for 10/7 but may have to be pushed back a couple of weeks due to my ankle. My surgeon has told me over & over that I must lose as much weight as possible by surgery day in order to make the operation safer & recovery successful.

Now that I've explained that part, my question is, does having an acute injury like a broken bone with swelling cause you to weigh more (extra fluid or whatever?) Could I be losing fat still but the scale not show it because I'm injured?