Hey Elaine....i was on seroquel a few months back for my anxiety, but after a week and a half it gave me the shakes and oculogyric crisis(where you cant control your eye movements), but not everyone gets that though, and it did help with sleeping a whole lot. But coz it is an antipsychotic, i was on Zyprexa last year for about 7 months and that did help immensely with the flashbacks...but it also turned me into a fat zombie! But yeh, i didnt mean to try and scare you with this, its just my own experience and hope it has helped some...
If your unsure as to why she prescribed it apart fromt he 2 reasons you listed and dont know much about it, maybe try asking her for a more in depth explanation as to why she has given it to you and what it can do for you...
Who knows though, it could be the thing your looking for!