Any idea what she's "mixed" with?
The reason I ask is this -- at one time I had a sheltie/corgi mix -- and when he was young I thot he was THE most neurotic dog I ever knew.
Now granted, -- I knew much *less* then than I do now and I'm sure I said/did much of all the wrong things. BUT something happened when Foxy was in his senior years that finally made it click for me.
A friend of mine with herding dogs had made *me* far more aware of how incredibly ingrained herding behavior is. Somehow we expect a hound to 'sniff' and laugh about it. But a herder WILL HERD. Part of herding behavior IS an awareness of the environment that is unique to herders. (which is why I thot of it in your description)
I used to be clueless why my dog would particularly get all upset in the car. Now riding down the highway? no biggie!! But try to go thru a parking lot or across an intersection where people were waiting for a bus and others crossing the street and traffice turning left or right?
O ... M .... G...........***HISSY FIT***
One day Mother Stupid (that's me) finally figured it out. Any time something in his environment (including TRAFFIC on the street) moved in an un-structured way -- it made him nervous!!!
As long as the traffic was barrelling down the highway in nice straight lines he was FINE. But people waiting at busstops? crossing streets -- THAT WAS MESSY -- it **REQUIRED HERDING**!!!!
And if that herding instinct was frustrated -- yep -- he was nutzoid about it.
Foxy too, lived thru tornados and it had a HUGE impact on him. A tornado sounds a lot like a freight train going over your head -- it left him hugely storm phobic. I developed my little "storm party" system and it really helped him on that issue. (literally as soon as it looked like it was going to storm, I'd give him some valerian glycerite tincture, gather all the goodies I could find food-wise and we'd sit and WATCH for a storm to begin -- every flash and boom I'd give yummy treats and "count" between them to get an idea of whether the storm was increasing or retreating and basically let him see it was PREDICTABLE -- rewarding both the flash and boom with treats.)
But once again -- it appealed to the herder instinct because I showed him some measure of predictability to the storms. All a herder needs is to know **someone** is in charge. And phew -- if it's not him he's often relieved.
My point is this -- if it is possible that your dog is mixed with herder (and I can't tell from your pic) -- then you may have better luck if you give him structured herding outlets -- games you devise to allow him to "control" aspects of his environment. Like toss a bucket of tennisballs in the air and ask him to 'get' them (a treat for each one he drops back in the bucket).
There can be many variations on that theme but the point being to let the dog have an outlet where they get TO herd and be rewarded for it.
A herder WILL know when every leaf drops, or a piece of paper flutters to the ground. So rip some paper up and toss it in the air making a game of picking it up.
Some have mentioned above about the usefulness of herbal or even drug therapy. The point being -- if a dog has moved from a normal (altho maybe naturally anxious) frame of mind to a high state of anxiety ALL the time, then you have to dial that back a bit so the dog CAN think and make better choices of what is really bad and what is merely "ok".
I could also defuse Foxy verbally -- if he came to be upset about some "thing" wrong in his world, I would ask him to "show me" -- and then we'd go look at it. That was my cue to say "Oh -- you're right -- Mrs. Smith's car is gone -- but it's Tuesday and thats' OK!".
Now -- maybe Tuesday doesn't have a thing to do with it -- BUT your prounouncement that is "is OK" is really what the dog needs to hear. That YOU know about it and are not concerned.
But how you handle it has to be very matter of fact and low key. You can't "oh baby -- it's REALLY okkkkkkkkkkkkkkkkkk -- tsk tsk sweetheart ..."
Nope -- just plain say "Yep -- you're right -- the driveway is empty -- thanks for telling me but **I know and it's ok!**"
There are homepathics like Heels "Calming" or even Boiron's chamomillia can be instantly calming as well. Valerian *in tincture* works fast, and homeopathics work fast -- so they're easier to work with in cases of anxious dogs rather than having to wait for something TO work.