the thing is. I already evolved my gloom into Bellossom but it's still not learning Sunny Day. Pls help.
Bellossom doesn't get it levelling up. You can take to the Move Relearner and teach it in exchange for a Heart Scale, though, as it is a level 1 move for Bellossom (assuming this is ORAS). It is less hassle to just give it TM11, though.