If you are suffering from PTSD and related psychological/mental symptoms, it is critical that you inform your employer of your medical condition, your specific diagnosis and your limitation, and request a meeting to discuss the accommodations that you might need in order to allow you to continue performing your job duties.
Keep in mind that under the law the employer does not have to read you mind and assume that you need a particular accommodation, and not worry so much about medical confidentiality. Therefore, it is to your great benefit to share all the necessary information about your condition and limitations, so that the employer has an opportunity to explore what accommodations may be available to you and how to make sure that you are able to continue being park of the employer's workforce. And if the employer asks for further clarification of your condition and your restrictions after receiving your original medical paperwork, you should be willing to provide it.