Individuals with a specific type of obsessive-compulsive disorder (OCD) commonly believe that they are developing a mental illness, often schizophrenia, because it’s considered to be the most severe and they fear it the most. They might become obsessed with the fact that they are going “insane” or developing psychosis. It is quite common. The thoughts that “pop into your head” are likely obsessions, a symptom of OCD. My sense of the situation is that your symptoms are most likely associated with OCD and not the development of psychosis but only an in-depth, psychiatric interview, with a mental health professional, could provide a diagnosis.
The fact that you have been diagnosed with OCD, and are being treated for OCD (rather than schizophrenia) increases the likelihood that your symptoms are not indicative of psychosis.
It is a concern that you are taking two psychiatric medications, yet continue to experience significant symptoms. It may mean that your medication needs adjusting. Report your symptoms to your prescribing physician who can then adjust your medications accordingly.
If you are not currently in psychotherapy, you should consider it. OCD is a complex disorder which often requires both medication and psychotherapy. One without the other is generally not recommended. Please take care.