Many orchids only bloom at one time of the year. They are very picky about the light they want in order to bloom. It is natural for the entire stem that the blooms are on to die back after it has finished blooming. I would drop back on the fertilizing until you identify exactly what kind of orchid you have and what it's requirements are.
Wrong ......My orchid bloomed in February, and was done, and right now in July it is going in to blossom again.. White Phil.
However I have another one in Pink just starting to set blooms first time.
4 other types not in bloom at all.
Just receive 2 new ones in the mail yesterday...
Love the Orchidas......
Ps are you using Orchid soil like tk gave me?