Is your plant the New Guinea Impatiens (Impatiens hawkeri) ? A photo would surely help in identifying the problem. Yellowing leaves can be caused by many things; too much water, too little water, etc. Fading and dying blooms are a natural occurrence; you can let the old blooms fall or remove them.
~ I'm an old gal who still loves playing in the dirt!
~ Playing in the dirt is my therapy ... and I'm in therapy a lot!
