I was on seroquel for a while too. It was AMAZING for sleep. Until I either acclimated or my brain started outpacing the effects.
I have racing thoughts based insomnia-takes me forever to get to sleep-anywhere from one to five hours, and dieties and scientific principles help me if I so much as twitch, because then I need to start all over again.
I've been off it for a year and a half now trying alternate meds but nothing works as well, so I'm thinking about begging the doc to give it another try. I'll do just about anything.
I also was on Gabapentin which is an anticonvulsant and nerve pain med, again off-label for sleep, and while it made me feel ever so slightly better, it didn't really help me get to sleep.
There were about three others, none of them strictly for insomnia, all of them off label, only one I had a bad reaction to (confused and mentally blurry to almost inability to operate), but in the end, none of them were what I was taking them for. I actually joked with friends about my anti psychotics at one point.
If you're concerned about your meds, taking a bit to talk to your pharmacist can help, usually where I am they go through it with me and then add in a small page with a description and cautions that I read on my way home. It only takes a minute and is done in time I would have normally just been staring out a window anyways.
I don't know what it's like where you live, but I hope it can help calm down any future anxiety about medications.