Tammy Sytch — also known as “Sunny,” in the ring — is behind bars over a fatal car crash from last month that cops say was caused by her being under the influence.

The former WWE star was arrested Friday night and hauled off to the Volusia County Jail — where she was booked on a number of charges … including felony DUI manslaughter, the most serious of the offenses. She was also rung up on 8 other charges, most being DUI related.

One charge she was booked on accuses her of driving on a suspended/revoked license, and then causing great bodily harm and/or death as a result. Her bond is set at over $220k total.

You’ll recall … this all ties back to an awful accident police say Sytch caused in late March — although it’s unclear why she’s just being arrested for this now, more than a month later.

In any case … the story is tragic. According to a traffic crash report, obtained by TMZ Sports, cops claim Sytch was traveling down a highway at a high rate of speed when she slammed into the back of another vehicle on the road that was stopped at a traffic light.

The driver was taken to a hospital but died from their injuries. That victim is reported to be 75-year-old Julian Lasseter.