What you describe is very typical for anxiety, the worries about being "crazy", the racing thoughts, high levels of anxiety, sleep disturbances, etc.
For one, you don't have to worry about being Schizophrenic. People with psychotic illnesses do not realize they are abnormal. Also, the term "nervous breakdown" was coined many decades ago, before a lot was understood about anxiety disorders. There really IS no such thing as a nervous breakdown.