Well just improve your conditioning and do abdominal workouts. it well definitely help you take a punch to the body better. But remember, no one is impervious to body shot, conditioning helps but not much. At least your not pissing blood like Ali when he fought foreman.

Going down from a body shot has more to do with pain tolerance rather than something being broken. One way to condition your body to take this punishment is to have someone beat your body using rataan sticks wrapped together and over some time you will take punishment better. Manny Pacquiao has been doing this for years and could withstand the best bodyshots that Cotto could land on him.

What you need is more experience. I'm sure you work out your core a lot, but that's not everything. You need to learn how to take the punch and only practice and help with that. Just like you can't make your face take more beatings, you learn to tough it out and dodge punches.

do abdominal workout and more and even more

do crunches and whatnot

I was sparring at my boxing club last night and took a massive beating to the stomach after I was done sparring I went into the bathroom and threw up because of the body shots. After that I had massive stomach pains. What are some workout or techniques I can use to build my resistance to getting hit in the body more specifically the stomach.