so I adopted a cat that is around 1-2 years old three days ago.She was doing really well, using the litter tray, eating fine and all in all settling in perfectly. But yesterday and today she just randomly started having 5-10 minute episodes where she is scared of everything, even her toys and what seems to be thin air. I’ve looked all over the Internet but can’t figure out what could be wrong and it seems to happen around twice a day, usually after eating. can someone please help me?
My best guess is that your cat is actually playing. Your cat is pretty young, and so it could have extra wild energy. Sometimes when cats get really hyper, they will run about the house wildly, really making a ruckus. Suddenly diving into hiding places can also be a part of play as well. Cats also tend to get more active or even hyper around mealtimes, which could explain the timing of the episodes.
I would try to really pay attention to your cat's body language while an episode happens. Is its fur standing up, especially on the tail? Are its dilated or normal? A scared cat's eyes will dilate. They also dilate when the cat is about to pounce. The cat arching its back may or may not be a sign of fear. It's a kitten behavior to arch their backs during play, but some adult cats will still do this too. If you observe your cat while it's definitely playing, and you see it arching its tail or back, often accompanied with a bounding sort of walk, it's surely one of those cats that arches its back during play.
If it turns out to be play, your cat probably just needs more vigorous play right before mealtime.
If it is definitely not play, then I think medical causes should be ruled out. For example, feline hyperesthesia is a relatively common but mostly harmless disorder that can cause a cat to bolt around the house in alarm. I would take a video of an episode if possible, and show it to your vet. You should take your new cat to the vet anyways for its first appointment, as it's a good rule of thumb to take any new pet for its first checkup as soon as you get it.
If the problem is also not medical, then my best guess is that something unrelated is scaring it. It could be for instance, seeing animals outside that is freaking it out. You will have to try to observe if there is any more pattern to these incidents to see if you can piece together what may be scaring it.