Hi My Name Is Sara, For About 3-4 Day Now

hi my name is Sara,
for about 3-4 day now my 11 month old american staffy puppy has been different and not energetic
dayn1: he was moping around
day 2: he was moping around a little scared and he wouldn't move from his bed at all
day 3: his moping around scared wont move he every now and then has trouble breathing wont eat wont go toilet wont lift his head when called or come and letting off really bad farts the smell is like something died and had been sitting there for weeks when i make him go out side to go toilet he goes out there but lays down for about 4 minutes then comes inside having trouble to breath and plonks him self
day 4: as above but his really bad today about 20 minutes ago i tried to get him to go toilet before but he just plonked himself wouldn't move or lift his head five min later he came inside all out of breath plonked him self next to my feet his just laying there with his eyes open and breathing like his snoring. he just walked outside but plonked him self out side the door he was out there for not even 2 minutes it was like he choked he tried to get back up he came back inside and is at my feet again his curled up with one of his front paws behind him.
PLEASE CAN YOU HELP ME FIND OUT WHAT IS GOING ON WITH MY PUPPY? IM 21 YEARS OLD ONLY WITH ONE INCOME COMING IN. I DON'T GET PAID UNTIL NEXT WEEK THE VETS WONT HELP ME BECAUSE I HAVE NO MONEY I'M SO UPSET