Thank you all! I think I got some bad advice. Someone told me to handle her as much as possible and for as long as possible to get her over her fear. I do know she's stressed when she's constantly slithering around on my bed, and that's when I usually put her back, but most of the time she just likes to find a place to 'sit' and look around. That means she's relaxed if I'm reading her properly, right?
I also try to pay attention to her breathing and when I see that she's breathing heavily I always put her back. However, I know snakes can still be stressed without showing visible signs.
Honestly the last thing I want to do is stress her out so much, I was just under the impression this would get her to be less afraid faster and would be better for her in the long run, but now I see she definitely needs to be left alone more. I think I'll leave her alone completely for a week and then start trying to handle her for 10 or 15 minutes every 2 or 3 days. Does that sound alright?
Edit: Just a note for anyone new to owning BPs that come across this thread: Never trust anything a Petsmart employee tells you.