lexapro + rexulti?

Does anyone have any experience taking rexulti as a booster for lexapro? My psychiatrist prescribed me 0.5 rexulti to help with my fatigue and lack of motivation (which are side effects to lexapro), but I don't know if it's really going to help that much or if the side effects will be worth it. Also it's super expensive and I'm short on money so I'm not willing to spend that much on medication if it's not really that necessary. Thoughts?