What Causes Constant Pain In Lower Abdomen And Tiredness?

I had a bladder sling and several meshes surgery 3 weeks ago due to severe prolapse. I ve had sharp pain earlier, and now I have a constant pain in the lower abdomen with a feeling of warm water running inside. I have not felt good all day and very tired. Is this something to worry about or just part of the healing. I am on hydrocodone for pain every 4 hours still.