Surgery upsets the digestive system and bowels - due to the anastesia (sp) that is why the laxitives were used -
I would bet if you relieve your stress allyalvin and get that water in you - you would feel better.
I had surgery two years ago and three days later had gained 13 pounds. I got a REALLY good laxative from the doctor and lost that 13 pounds in one afternoon, lol. The body retains water among other things after trauma to it. Try to drink lots of water to flush it out if that makes sense.
JUst so you know - it is not uncommon when the body is totally stressed out - it will retain water - so I would suspect this is the case.
Also depending on the biopsy - the body doesn't really like getting pricked like that so again it will retain water too.
I would dring alot of filtered water for the next 2 days and get some exercise to balance your nerves. I bet those pounds will leave you as fast as they came on.
Good Luck with the results on the biopsy.