Hello,
Both Prozac and
Neurontin cause
insomnia rather than increased sleepiness. It can be due to not getting enough sleep, drug, alcohol, or cigarette use, lack of physical activity, obesity, the use of certain medication, depression, restless legs syndrome, sleep apnea, or narcolepsy.
You need to get it evaluated from a sleep specialist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided.