Op ive not been through stranger rape but other rapes. The nightmares and flashbacks can be dealt with through EMDR - it's the trauma therapy used with soldiers (US, UK and Australian from what I know) and works for the majority. It doesn't take away the actual memory, but it makes all the triggers "normal". So if, for example your attacker was wearing a red t-shirt and every time you saw a red t-shirt you dissociated/had flashbacks/had a panic attack, after the treatment you would just see a red t shirt and not have those reactions. It also means the memory of the event gets "neutralised" so you can recall it (you don't forget), but it's like talking about walking to the supermarket, or sitting on the bus: there's no horrible, scary, panicky feelings with it.
If you've not been offered or tried it, then I highly recommend you ask for it. I also can't pretend it's easy to do, but what you've gone through and are going through aren't easy either.
You are not going crazy, you have been put through something that was too much for your mind to cope with, but it can get better - and this method is proven to work. There's a lot of research on it and they can't understand why it works, but it is proven effective (and like I said is used on veterans),and best of all, assuming your rape was a one off, would work pretty quickly too.
If your MH team for any reason don't have someone who practices it, then I suggest searching online for someone near you who does and asking them if they think they could help you. If you can't afford their fees, ask if they ever do reduced rates, or know of another therapist who does it who does - because some do, especially for something like this.
Nobody can undo what this bastard(s) has done, but the symptoms certainly can be helped so that life becomes worth living again.