Olanzapine is an antipsychotic drug. It is given in psychotic illnesses like Schizophrenia, Bipolar Disorder etc. If you were given this drug "along with other drugs" just to help you sleep, then you may want to talk to your Physician. If you are having a Psychiatric illness and were prescribed Olanzapine as a part of the treatment, and the doctor was a Psychiatrist, then it may be justified.
Next Steps
Talk to your Physician. If you have trouble sleeping then that needs to be evaluated. Do visit a Psychiatrist in any case and have yourself evaluated.
Health Tips
Olanzapine does induce sleep among other effects. It's never the primary indication for its prescription.