unfortunately the stress and you recovering from the surgery aren't going to help matters. Have you seen a lactation consultant either through your doctor/hospital or La Leche League? They might be able to provide more personalized advice. Unfortunately if you only nurse him a couple times a day rather than every 3 hours or so, your body is going to think it doesn't need to make that much milk. Even if you supplement after, you should have him latch on first to signal to your body it needs to make more milk.
For nursing position, are you able to lie on your side and have him lie next to you? It will keep the pressure off your incision. I use this method at night when I don't really want to sit up because I'm tired. You can also use the football position where you hold the baby next to the nursing side rather than lying across your belly.
My DD was huge, born 9lbs 4oz and into 3-6, 6 month clothes by about 7 weeks. Thankfully I had no supply issues, but I stayed at home and didn't have any complications other than having a c-section, but the LC came by and gave me some advice on her latch and they were available if issues arose after delivery.
Best of luck to you and every little bit of breastmilk helps.