I used to take Seroquel. I don't know if it caused weight gain because I was put on some other meds at the same time. And I was put on Zyprexa for a bit-a huge weight gainer.
Could you replace Seroquel with Abilify if you still needed something? That's supposed to be weight neutral. I take it. Works great.
I'm also 5'4 and I got up to 191 pounds. Then I developed anorexia after a while. I'm at a healthy weight currently.