Thank you for the additional information.
Dizziness and a spinning sensation that has been present for only one day (or a few days) is most likely due to inflammation of the inner ear, called labyrinthitis. Any inner ear problem can be worse in when the head is in certain positions. And the primary cause of labyrinthitis is a viral infection. These acute episodes will typically resolve spontaneously, but there are some interventions that can help to ease symptoms until it resolves. Just like other common viral infections, there is no medicine that directly eradicates the virus, so we use medicines to relieve symptoms.
The usual first step are certain antihistamines that ease the dizziness/spinning sensation. Meclizine is the medicine that is used most often and is over the counter in most countries. Other antihistamines that are marketed for motion sickness also can help, such as dimenhydrinate. Even diphenhydramine has some activity against the dizziness/spinning.
In someone with more severe or persistent symptoms, another option would be a short course of steroids, to ease the inflammation, but this would typically require seeing your doctor. There are also some stronger medicines to suppress the dizziness/spinning, such as diazepam, but these also would require a prescription.
So, the first step would be to use one of the antihistamines for relief of symptoms, but if the symptoms are severe or persistent, then you can see your doctor for consideration of steroids or a stronger medicine to suppress the dizziness/spinning.
If I can provide any additional information, please let me know.