Most orchids go dormant in the fall and drop their flowers at that time, so it's a bit odd that your flowers recently fell off -- unless you purchased the plant from somewhere other than a nursery, which would mean it was forced to bloom and is now off-cycle. With the proper care, your orchid will bloom again. This article may help you: https://www.gardeningknowhow.com/ornamental/flowers/orchids/how-to-prune-an-orchid.htm
When an Orchid is done blooming the flowers will wilt and drop off.
The plant then needs a dormant period. This is the plants life cycle and it is resting and storing up energy to rebloom.
Here are some articles that will help you with care.