Girl, Immortal by Graceley Knox

Back from the brink of death and still fangy.

Sasha Keleterina is one of the few vampires who have survived the deadly sickness spreading through vampires like wildfire. And now that she’s back at full strength, she’s determined to end this war, once and for all. Just as soon as Arsen convinces her that they’re meant to be together for all of eternity.
Nikolai has other plans, including keeping Sasha all to himself, even if it means the end of his rule over the Baetal. As Sasha and Arsen follow him across the country, cleaning up his disasters one after the other, tensions rise between Jackson and the vampires they’re trying to save, making distributing the cure, that much harder.

When Nikolai threatens the life of one of Sasha’s allies, it’s up to her to make things right.
Even if that means sacrificing herself.