If you're thinking about using any martingale use it FIRST when lunging. She's already edgy, and I think a standing or running martingale might make her explode, so better to be on the ground and watching, than to be aboard her. I think your mare has a gap in her education. Being a mare she may have been bred THEN broken. A year off perhaps reminds her of her "Life of Riley", and I think she'd rather not work. Or, she may have been rushed when broken. Horses have an awesome memory for bad experiences.
I have both martingales. I used a standing martingale on my babysitter QH ("Ro Go Bar", 1982-2009, RIP) bc he would throw his head when at a halt at Reenactments (often during the battles). With the martingale, the head throwing ceased. I have used a running martingale when I wanted to keep one of my horses under better control with a snaffle, and I would keep it on IF my horse didn't get fussy with it.
Back off of the schooling you are doing with her.
Take her back to the basics, and praise her for everything simple that she does correctly.
I was taken back recently while watching "Dressage Symposium" RFD-TV :: U.S. Dressage Symposium
Michael Poulin commented that we don't give our horses enough praise and asked the audience to consider the punishments during a schooling session and whether they also praised their horse. Often we just expect our horses to perform after they've mastered a skill like an automan. They really do want to please us.
Horses are not children. They won't get arrogant and turn into little monsters just bc you vociforously tell your mare she did a good job. I've only owned 6 mares (vs ~ 25 geldings), so when I bought my great mare 3 years ago, I decided to make her feel special. Now she ALWAYS comes up to me in the pasture, and I let her do things that her 5yo herd mates don't get to do since I can't trust them like I can trust HER. I tell her what we're doing when we work, and she says, "Okay, 'Duck!'
) (Duck is my family's nickname for me, lol.) She'll blow, "hello" when she's near me at the fence or gate. I think if you can go back and get your mare to trust you, you'll be able to work through this. Sorry for the treatise!! =b