I can’t make a diagnosis on the basis of a letter, of course. But someone has. You could not be prescribed medication without a diagnosis. Go back to your prescriber and ask for that information. Then talk about the fact that your medication doesn’t seem to be enough to quiet your symptoms. You may need a different medication or a different dosage.
You certainly need to be talking to a talk therapist as well. If you connected with one of the therapists you’ve seen in the past, please make an appointment for further care. If you didn’t connect with any of the therapists you’ve seen, ask yourself how it is that you haven’t stayed with any one therapist in order to get treatment you clearly need.
I suspect that your paranoia and trust issues are played out in therapy just as they are in your every day life. If that’s the case, it’s something to talk about with the therapist, not a reason to flee treatment. To get better, I think you need to make an appointment with a therapist and make the commitment to talk right from the start about whatever makes you want to leave therapy despite the fact that it would probably be helpful to you.
I wish you well.