Clonazepam is a benzodiazepine
drug having anxiolytic, anticonvulsant, muscle relaxant
, sedative, and hypnotic properties.
More common side effects with this medications are
Interference with cognitive and motor performance
Irritability and aggression
Lack of motivation
Loss of libido
Impaired motor function
(common with higher doses)
As you can see menstrual disturbances are not the common side effect of this medication although it can happen as a rare side effect.
Please consult a doctor if the problem persists.