I Had Lumbar Anterior And Posterior Fusion Surgery 7/18 And

I had lumbar anterior and posterior fusion surgery 7/18 and my hip area is so swollen plus have gained weight though I am eating very little, though of course not moving as I did before as I was a runner. I am very health conscious and a vegetarian. I was on a liquid diet for 3 days post surgery in the hospital and now can eat regular foods but a little food fills me fast plus gives me a stomach ache and cannot eat more. I am very concerned and worried at my weight gain. Will the weight go down once the swelling lessens? How long will that be? It is now exactly one week post surgery for me.