Oversupply ..very frustrating

My breasts are full most of the time and breastfeeding my baby is very frustrating since he is hungry but he is frequently choke at the breasts, resulting my baby screams and does not want to continue sucking.

I tried to lean back while breastfeeding, it does help sometimes. As the letdown reflex comes, I pull my baby out and let the sprays soak the burping cloth. I wet 1-2 burping cloths at each feeding. My baby gains weight fast and yes, he does have lots of gas, he screams and cries a lot when he has gas pain.
I am returning to work so I pump out and bottlefeed him. Look like with less sucking, my milk supply is reduced; however, I still breastfeed him at night and milk still sprays everywhere (even when my breasts are not full and tight).

I am very frustrated, why can't I be normal like other moms?