This is Prowl (2010).
Amber dreams of escaping her small town existence and persuades her friends to accompany her to find an apartment in the big city. When their transportation breaks down, she and her friends gratefully accept a ride in the back of a semi. But when the driver refuses to stop and they discover the cargo is hundreds of cartons of blood, they panic. Their panic turns to terror when the truck disgorges them into a dark, abandoned warehouse where blood-thirsty creatures learn to hunt human prey, which, the friends realize, is what they now are the human prey fighting to save their lives the realize they must work together but will they survive..
The main character, Amber, is an 18-year-old girl who -- upon learning from her alcoholic mother that she was adopted -- decides to leave the small town she grew up in to rent an apartment in Chigaco. A friend agrees to drive her there and a few more friends tag along, but their car breaks down in the middle of nowhere. They then hitch a ride in the back of a passing semi-truck, which turns out to be loaded with cardboard boxes full of blood bags, and are driven to a dark, abandoned warehouse populated by vampire-like creatures with mostly black eyes. The word 'vampire' is never actually used in the film, but they drink blood, have sharp teeth, can crawl up and down walls and leap inhuman distances. They're led by a woman named Veronica, who mostly keeps her distance as they attack and kill the main characters.
In the end...
... when cornered by a large number of the creatures, Amber instinctively leaps high up a wall and clings to it. Veronica then comes forward and explains that Amber must be one of their kind -- a "late bloomer" who's "finally awakened" -- and that's she's been taking in and training other stray members of their kind for years. Amber asks if Veronica is her mother, but Veronica says she isn't, and that birth amongst their kind is a "violent process" which almost always kills either the mother or the child, hence the large number of orphans among their kind, Amber included.