Mine turned yellow too. Unless there's a foul odor or you're having itching or burning its probably normal. But you can always call your ob and check.
It sounds like lochia, which is a completely normal discharge. Unless you're having other symptoms of an infection, or an excessive amount of it I wouldn't worry about it, I actually got that for quite a while after my bleeding slowed down.
I'm assuming the discharge is coming from your vagina, correct? To me that sounds like an infection of some kind and should be brought up to your doctor ASAP. I never had any discharge after mine just bleeding like a period.
Well idk anything about csections but I think any discharge w/ an oder / color is definitely a concern I would make an appointment w/ them they'll probly get you in fast