According to your description, it seems that you are probably experiencing anorgasmia, in other words you canât reach an orgasm. This particular episode of anorgasmia is probably a secondary condition because you have had orgasms in the past.
Main reasons for anorgasmia are not enough foreplay or psychiatric disorder. Some antidepressant drugs like Selective Serotonin Reuptake Inhibitors (SSRI) can cause anorgasmia. Prozac (Fluoxetine) is one of the SSRIs. Besides using Prozac, climax can also contribute to the appearance of this sexual dysfunction. You can consult a psychologist or psychiatrist about your condition.