Remember Me Tomorrow by Farah Heron

A missing student. A singular investigation. A new romance. Every bit of it is a mystery in a delightful novel of cosmic twists by the author of How to Win a Breakup.

East House is the oldest and least desirable dorm on campus, but it has a draw for lonely university freshman Aleeza Kassam: Jay Hoque, the hot and broody student who vanished from East House five months ago without a trace. It’s irresistible to an aspiring investigative journalist like Aleeza.
But when she starts receiving texts from Jay, the mystery takes an unexpected turn. To put it mildly. His messages are coming not only from Aleeza’s own dorm room but from the past—only weeks before he disappeared. Sharing space, if not time, Aleeza and Jay are living the impossible, and they start working together to prevent his inevitable disappearance. Causing a temporal paradox that could blow up the universe is a risk they’re going to have to take.
Aleeza digs through Jay’s suspicious friends, enemies, and exes, determined to find out what happened to him. Or what will happen to him. But it’s becoming more than a mystery. Aleeza is catching feelings for her charming new roommate. Wherever, and whenever, he may be.