I had a right hemi and after a day in the hospital I started bleeding. I understand this was a leak caused by the surgery. I couldn't eat the first few days (no appetite) and just drank water, and the output, like you mentioned was dark red in colour. I was in the hospital for 6 days and it had pretty much cleared up by the time I left, without any intervention. So my bleeding lasted about 5 days, which is about where you are now.
It seem they discharged you, knowing of this problem, so did they give you any instructions? As others have said - let your doctor know if there is no improvement.
May 2015 right hemi CC cecum
removed terminal ileum, illeocecal valve, appendix, cecum and ascending colon, omentum
stage 3b T3 N1b MX 2/27 nodes (isolated tumour cells in 1 additional node)
PNI - positive
LVI - positive
Folfox 12 sessions (oxi discontinued for 11 & 12)
Neulasta with 3-12 due to low WBC count
CEA at diagnosis 8.6 and after surgery 1.2
CEA during chemo 4.6 / 3.3 / 2.3
CEA after chemo 1.5 / 1.2 / 1.2 /1.2 /1.2 / 1.4 / 1.1 / 1.2 / 1.9 / 1.3 / 1.6