Seroquel is an antipsychotic, not a mood stabilizer, but getting the thought disorder issues under control using seroquel can have mood stabilizing properties. Seroquel has not been shown scientifically to reduce suicidality. Only lithium has. So when they tell you seroquel will not reduce suicidality, they are talking about the scientific evidence, not personal anecdotal evidence.

Otherwise, seems like you just need to keep working to find a pdoc that will work with you. The letter does a good job of listing out your symptoms and experiences for them, so hopefully you will find someone who will work with you soon. Good luck to you.