That is strange. People sleep on as little as 50-75 mg of Seroquel, and in such low doses if does not cause massive weight gain. 600 mg seems an overkill, unless they also were trying to treat something else besides the sleep problem. I almost think that it is possible that at high doses Seroquel is not sleep-inducing but at low doses, it is.

Every p-doc should have a way to connect with you in case of emergency. You said you called your p-doc 4 times; did they not return your call??

Benzos are medications such as Lorazepam (Ativan), Clonazepam (Klonopin), Temazepam (Restoril), Diazepam (Valium)... have you ever tried them?