Hunter of the North - The Ward Series, #2

STACEY TRAMPLER'S FIGHT CONTINUES ... AND THE WARDS WILL NEVER BE THE SAME AGAIN. Two years after her deadly battle with the Umbra, Stacey has a new threat to contend with, after having sacrificed so much, and lost so many people: PTSD. Fanta, her trusty German Shepherd sidekick, and her best friend Charlie are by her side luckily, or she would have lost it long ago. But when a new street drug in America starts turning people into Umbra infected monsters, her anxiety attacks and flashbacks of the horrors she faced become far worse.
Having to put down the very people she's sworn to protect, and struggling with nightmares that she isn't sure aren't visions of a a far greater threat, Stacey's already taut nerves are ready to snap. And she'll break with them if she can't find a way to cope. If Stacey can stay sane and alive long enough, she might be able to unravel the source of the drug and put a stop to it, and find some level of peace ...
at least until the next attack.