Chronic insomnia (not total sleep deprivation) doesn't cause psychosis or hallucinations does it? i have a huge fear of going crazy (ocd) and this worries me a lot because i've had trouble sleeping .

Not likely.: Mild to moderate insomnia in and of itself is not likely to cause psychosis.

Possibly: The symptoms you are having could be from several sources and a good general check up is a good place to start including complete blood studies. First things first. The results may direct further treatment as needed and can also rule out issues also.

Anxiety and sleep: Not sleeping, such as chronic insomnia, can have adverse affects on the brain. This can cause increased anxiety, which can include an increase in your ocd symptoms. Finding a good therapist to work through the issues which are causing you sleep disturbance would be beneficial.

Just obsessive worry: Only prolonged sleep deprivation can cause psychosis. Practice good sleep hygiene and if your sleep problem persists, see a sleep specialist.