My golden is terrified of thunderstorms - tried everything, nothing works

My 4-year-old golden Luna has been afraid of thunderstorms since she was a puppy. We're talking full trembling, panting, pacing the entire house. I've tried the thunder shirt, calming treats, a white noise machine - none of it makes much of a dent.

Last week we had a big storm roll through and she was inconsolable for almost two hours. My husband sat on the floor with her the whole time. She's such a brave dog normally - she'll walk right up to any stranger, she loves kids, she's totally fearless at the dog park. But the second the sky darkens she completely falls apart.

Has anyone else dealt with this with their golden? Did anything actually work? Our vet mentioned anti-anxiety meds but I'm hoping to find something that doesn't require medication first.