How can i gain that muscle?!?

Well right now i wen to mcdonalds order 3 Quarter pounders combos then i look down i got 4 layers of extra meat muscle on me and i want to look good on my dress before my brothers wedding!!! right now im XL women (special made clothes) the one i bought (costed 671$ no joke) and its sized XXL please i need to get at least 1 more size help!!!