Please help my betta is sick?

[Veronica]

so i've only had my beautiful delta tail betta for 4 days, he is in a 2.2 gallon tank, which has a filter. I am going to buy a heater but couldn't find a 7.5w one, but the house has been a pretty consistent 76 degrees since i've had him. The first three days he was fairy energetic, and he seemed healthy when i got him. But now all he is doing is lying on the bottom of the tank, and swimming to the surface for air every minute or so. i know he is not just resting, he has been doing this all day. i have done one 50% water change but i don't want to stress him out more by doing another one. I use a water ager and aquarium salt, the ph reading is a little high at 7.2 and i don't have a test for ammonia or nitrates as ,my LFS that it wasn't necessary if i did water changes every 3 days. I turned the filter off just now because i thougt maybe he was having trouble with the current but no change. He has other symptoms, his fins are clamped and he refused to eat anything other than half a blood worm yesterday, and he also has yet to poop. His colour seems normal, but he does have lighter patches around his face but i don't know if that is just his colouring. Please please help, i've given him a dose of bettafix, what else can i do? I really don't want to let this poor little guy down.