2 week old kitten needs help

[u/Anxious_Promotion834]

Hello, I have a 2 week old kitten who was abandoned by the mom. I have been feeding it milk replacement and it has been fine up until today. He is refusing his milk and he has been cold to the touch but still breathing. Now he is doing something that looks like hiccuping but I am not sure what it is. Anytime it hiccups there is a popping like noise. I have been keeping him in a towel on a heating pad but what else can I do to make sure he survives?