If Seroquel is not helping with hallucinations at the very high dose of 900 mg, it is not "your" drug. You need to look for another AP that would work. Who is your p-doc? Why are you treated with such incredibly high dosages of drugs? And they are not helping you "to boot". Maybe you need to change your p-doc, but at this very point the safest route is through the hospital.

Additional food for thought: an "unsuccessful" suicide attempt (and most attempts belong in this category) can make you permanently maimed. I almost lost my left arm because in my chosen method of a suicide attempt, I left home without a cell phone and parked the car in a very distant business park on a Sunday evening, and OD'd. I was not found until 8AM in the morning when security started patrolling the parking lot. Apparently the way I fell asleep sitting in the car I pinched some nerves in my left arm or something, but at any rate, when many days later I finally woke up, I could not raise my arm at all, and felt a lot of physical pain. I was on Tramadol for pain for many months after that incident. Ultimately, I lucked out - I regained 100% function, have the full range of motion, and am pain-free. Absolutely pain-free. (I had no liver damage either). The reason I even remembered it today: I cut my left thumb when chopping vegetables... not badly, just a bit, but there was blood and it took some dexterity to manage holding a sterile gauze in place while finishing the work of chopping. Such a minor cut on the LEFT (I am right-handed) hand made this very mundane task of chopping challenging. What would I have done if my whole left arm could not function? Imagine waking up and having ALL the problems you are currently having still present AND on top of them having to deal with physical pain for the rest of your life! Better go to the hospital now - it sounds like you have insurance for the meds so you probably have some coverage for inpatient, too. Probably not a lot, but at least something. Do you?