How can I help my horse settle in?

Sounds like you are doing the right things so far. Rescue remedy may or may not work, but it might be worth a try. Do you have other horses? If you do, find one she gets along well with and put it in the stall or pen next to her to keep her company. If you dont have other horses, make sure you are giving her LOTS of attention and love. Im sure you know that horses are very social creatures and hate to be alone. When you are with her, make sure you talk softly and pet her a lot. Im sure she would love a treat or two as well. Is there a certain spot she likes to be rubbed or scratched? Try to find it. Generally avoid stressful situations with her, such as trailering and moving her from stall to stall, if at all possible. Just keep doing what youre doing, Im sure she'll settle in soon.