Lunatic Louise!

I don't know what got into Louise today but she was really behaving strangely!
Thelma and Louise are very obedient dogs, but today it was like Louise forgot everything she's ever been taught!

Louise is such a character. If you so much as glance in her direction she's ready to jump up and say hello and get cuddles. She's not a puppy- she's already going grey around her muzzle- and she and Thelma were both spayed long before we adopted them.
I first noticed it when I had to pop out to the supermarket early this morning and as I pulled away she was trying to squish through the bars of the gate to get out! She's never done that! I immediately stopped the car to see if there was something she was trying to get to and she took to whining and wiggling her whole body and yapping at me. I walked back into the garden and she made a mad dash to get out the gate behind me! This is so not like her! I called her back in and then after a short wait to see if she would calm down, I called her and Thelma outside with me to see if they could show me something I couldn't see, but they both just ran around sniffing excitedly and aimlessly- like they do when we go for a walk- so I sent them back inside. Louise just wouldn't listen. She was jumping up on me and yapping and barking and throwing up little bits of the food she'd had for breakfast, and when I got back in the car she again took to trying to push through the gate!
I phoned as I pulled out the driveway and asked my hubby to have a look at her to see if she was perhaps hurt, and I went to the shops.
Glugs couldn't find any injuries or marks on her, so he tried to put them inside on their overnight mattress to see if she would calm down- no go. She wouldn't stay on their bed like they usually do, she was all over the place and whined and whimpered until Glugs let them outside again.
I called the vet who assured me that any kind of poison would have the opposite effect to making a dog all excitable, but suggested I try to keep her somewhere quite and calm.
After a bit of a stroll around the garden with both dogs I called them inside again, to see if I could get her to stay still and calm on their mattress. It worked to a degree, but she remained very fidgety all day.
I don't understand her behaviour at all. The girls have been with us for a little over a year now, but I've never seen such a huge switch in her mannerisms.
She did her busies as normal. She was eating and drinking water. Thelma behaved exactly as she does all the time- well behaved and obedient and calm- but Louise was bouncing all day like she'd been sipping Red Bulls on the sly!

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Monday morning update - we went to the vet this morning. She gave Louise a thorough once over, checking her temperature and everything, and diagnosed her with kennel cough!
The irritation in her trachea is what's making her drool and gag so much foamy spit all the time, and her sore throat was making her behave so strangely. This all comes before the coughing actually starts. She gave Louise a shot of some anti-inflammatories and I was given some cough mixture and tablets for her to take every day.
And because its contagious we have to keep an eye on Thelma too.
Louise most likely picked it up from another dog whilst out on a walk, and like with most diseases some dogs are more likely to catch it than others.
I am so glad its treatable and that we caught it early.
It pays to know your dog well and be able to tell if something's up.