I had my tummy tuck 4 days ago and I'm only draining 30 ml/24 hrs if not less with a lot of air/space in tubes. is this normal?

I have had bowel movements, I have a very low sodium diet and drink plenty of water. My doctor's office recommended I try to be more active, which i did as best as I can as Im only on day 4 post surgery and it still doesn't seem to be draining anymore. I'm starting to feel my tummy area is swelling. Should I be worried?