"I am going to explode!"
(1) My impression is the Korean verb 터지다 is used very much like the English verb "to burst" ...
(나가) 터진다 = I am going to burst; I am bursting (--> I need a 화장실 urgently).
To use it to describe emotions e.g. joy, pride, irritation/annoyance etc., the emotion needs to be specified.
환희가 터진다 = I am bursting with joy
자부심이 터진다 = I am bursting with pride
짜증이 터진다 = I am bursting with annoyance [ a restrained way of saying "I am going to blow up"]
(2) In Korean, the present simple can be used to describe the imminent future.