Why is there a sudden increase of fluid in my drain? It was putting out only 15-30ccs per day for three days, today 120ccs?

I am 4 1/2 weeks post op and had three drains two have been removed in that span but one remains, now I am experiencing a lot of fluid, fever and very sore and tender in my abdomen almost feels like it did the first couple of weeks following surgery. Is this normal? I am on antibiotics but still in a lot of pain. I hope I didn't mess anything up or tear anything. Other than this recovery has been smooth and healing very well. 14lbs of skin was removed from my abdomen.