I'm sorry, I haven't been on any sort of medication for something like that, so I can't give you specific advice.
But here's something that I feel you should know, whether or not it will help you, I can't say, but I feel it's worth mentioning.
I developed some heavy paranoia after being under surveillance a few years ago, for crimes that friends of mine committed. I was being watched and followed nearly everywhere I went, I couldn't even go out and have a drink with friends without noticing I was being bloody stalked.
I began to ruminate about it constantly, and it severely negatively affected my everyday life and mental health.
For an unrelated reason (being vegetarian) I decided to try taking a supplement called Acetyl L-Carnitine. I noticed when I started taking this supplement, my paranoia and overactive thoughts improved a lot. I would be able to go outside and travel without immediately being on edge and looking around for prying eyes. And when I noticed them anyway, I was much more centered and unaffected by it. The thoughts didn't wind up and escalate as much.
Fascinated, I looked into why, and found that Acetyl L-Carnitine supports healthy levels of the neurotransmitter acetylcholine. I don't know if my problems were caused by vegetarianism or stress from being spooked, or both, but this explains why it helped support normal brain function and healthier mood for me at that time.
To give you an idea of what the implications of that are, there's drugs in nightshade plants such as datura and some travel sickness medications, that are 'anti-cholinergenic', which means they stop the production of acetylcholine in the brain. This is a big reason why hallucinations, bizzare thoughts, and odd behaviour occur in people who ingest belladonna, brugmansia, jimson weed, or too many Travacalm tablets (scopolamine).
This simple supplement basically does the reverse of what these madness-inducing deliriants do.
I don't know if this will be much help, but you can find it in health food shops and it's probaby worth a try, even as a complementary treatment. It's mainly marketed for fat-burning and exercise.