It sounds like a type of vertigo called BPPV (Benign paroxysmal positional vertigo). This can cause intense vertigo which only lasts a few seconds to just under a minute but it can enough to make you actually fall down and be unable to get back up until it passes. I get this often and the first time I got it, I went to the doctor expecting to hear I had something deadly because the vertigo attack came on so suddenly and I literally fell to the ground due to it. I also felt very panicky, nauseous and unsteady on my feet after it for an hour or so. I've had it many times since and it still scares me when I get it. I literally felt like someone grabbed me and pushed me to the floor and spun me and the room around when I first got it. I didn't ever think I could experience dizziness that extreme.
Past ear infections, moving your head certain ways and inner ear conditions such as Meinere's Disease (what I have) can cause it. Its not serious but feels horrible and can be dangerous if you got an attack while outside and near a road or something but its not usually the sign of a serious condition.
I'm not saying that is what it definitely is but it does sound very, very similar to my experiences with BPPV. If your dizziness continues or gets worse then I would advise calling up NHS111 to see what they advise but for now, try and rest as much as you can.