I am so sorry to hear you are having this difficulty. My best advice (which isn't much) is that you speak to your psychiatrist about this. Do you also see a psychologist? Sounds like too that you have been adjusting meds and trying to get to a stable spot. But that lack of sleep in itself can make us feel crazy as you say. While benzos are not good long term, I worry about you not having that to help through this. Stay close to your doc and hopefully you can find the right balance of everything to begin feeling better. By the way, did the disassociation start three months ago?
Did you say you quit dalmane abruptly without tapering off? You don't need more problems -- and have you done this before with other meds? These meds have to be tapered off of slowly or you can suffer significant withdrawals. For some people they can last a long time and create problems you didn't have before. Using bentos for sleep can be a long-term problem, as you say, because they tend to stop working if you don't up the dose, they are addictive, and they can interfere with REM sleep and create rebound insomnia. Not being able to sleep is horrible, but stopping a med was the only way it ever happened to me. You want to be careful out there. But if you're truly bipolar, there is no known cure and the only control is medication. So finding one that treats bipolar and works for you and is tolerable to you is your main problem. As for seroquel, it's a sedating drug unintentionally as a side effect and was marketed for sleep illegally by the manufacturer. Taking drugs for their side effects is legal for doctors to do but you have to wonder about it because the drug is also doing what it's supposed to do and you might not need that effect on your brain. You need to really put your head together with a psychiatrist you trust who will work on the bipolar and I'm hoping that if you successfully get that under control, the rest of your problems will ease up.