I don't think that cats have panic attack episodes like humans do. Based on your cats history of the megacolon impaction, feeding tube, etc I am worried that she isn't eating well. When cats are very sick like that and then they stop eating, their liver can become overloaded and shut down. This results in something called "hepatic lipidosis" which essential means "fatty liver", and thus causes liver failure. If the liver failure is severe enough, the cat can get a build up of ammonia in the body and develop neurolgic signs. These signs include a dazed and confused look and acting drunk-like. The most severe result is seizures.
There certainly could be other causes to her behavior last night: other neurologic disease, low glucose from not eating enough, cancer that has spread to the brain or other places, and other metabolic problems.
I would recommend you take her back to your vet for an exam and blood work. The blood work will check the liver values, glucose and other values that could be contributing to her signs. I would check blood work again, even if you just had it checked a few days ago. I have seen blood work drastically change overnight before.
For now, I would continue to syringe feed her with a high calorie food
. I have seen this happen before where a cat has the feeding tube removed and then they quit eating. I think that their GI tract has just kind of shut down from having the feeding tube in, and that they might be nauseous as well. Ask your vet about giving her an anti-nausea injection. Also, you can try to give her 1/4 tablet 10 mg Pepcid AC to decrease any stomach acid she might have. Lastly, I often put these cats on a drug to increase their appetite- ask your vet about this too.
In addition, I would give her vitamin B 12 injections under her skin (ask your vet) and acupuncture to help her feel better and get her GI system and liver in a better place.
I hope this helps, and let me know if you have any other questions.