Spinning around in a chair almost made me have a seizure or something similar to a seizure. i still don't feel right. is this normal?

Vertigo: Will bet that your spinning stimulated the inner ear, vestibular apparatus, and you experienced vertigo, and maybe nausea. In most cases this resolves rapidly over several minutes to a few hours at most. If you are dehydrated could be much longer. If no rapid resolution, contact a physician. This is not epilepsy or seizure problem.

Seizure?: Was anyone else around to witness the seizure or whatever it was? If you truly had a seizure, no that is not normal and an eye witness account would be critically important to have. On the other hand, what you have experienced could be normal, depending on how long and last you spun and on what medicines you had on board at the time.

Vestibular System : Spinning around in a chair may have offset your vestibular system (a neural circuit with cells in your inner ear that can detect balance). It is unlikely that you are having a seizure, but if you continue to feel dizzy, i would recommend seeing a neurologist.