Mackenzie Shirilla Texted About Experiencing 'Blackouts' Weeks Before Crash

Mackenzie Shirilla claimed she was struggling with "blackouts" just weeks before the crash that killed her boyfriend, Dominic Russo, and friend Davion Flanagan ... according to text messages obtained by TMZ.

The messages -- exchanged between Shirilla and Russo, weeks before the 2022 high-speed crash in Strongsville, Ohio -- show the then-teen discussing episodes where she would lose awareness or suddenly black out.

In early July of 2022, Mackenzie texts Dom saying she recently had one of the worst blackouts she's had ... adding she's "scared it's just gonna get worse."

In the alleged exchange, Dominic seemingly tries to reason with Mackenzie by adding she may be vitamin deficient, which could be affecting the blood flow to her brain ... before the convo escalates to yet another argument, with Mackenzie telling Dom, "Keep treating me like this see where that gets you."

As previously reported, prosecutors argued Shirilla intentionally drove the car into the side of a building at roughly 100 MPH without braking, killing Russo and Flanagan instantly. Surveillance footage and data from their cell phones and the car became key evidence during the trial.

The defense, meanwhile, disputed claims the crash was planned ... and Mackenzie's mother maintained Mackenzie struggled with a disorder known as POTS -- a medical condition that affects the autonomic nervous system, causing an abnormal, rapid increase in heart rate and symptoms like dizziness or fatigue.