How can I tell if I have a regular ear infection or labyrinthitis?

Ear infection. I hope I am understanding your question correctly. When you say regular ear infection, I think you are saying otitis media or infection of the middle ear. This generally causes ear pain, sometimes ear drainage, hearing loss, fever. When someone has labyrinthitis, the infection is now involving the inner ear affecting the balance canals and the cochlea. This will usually cause severe dizziness.
Dizziness. Regular ear infections usually do not cause vertigo. Labyrinthitis usually always is associated with severe vertigo and nausea. You may also have hearing loss and tinnitus.

Related Questions

Can you tell me are the only ear infections that cause dizziness labyrinthitis and vestibular neuritis?

No there are others. Trauma, cholestetoma, fistulas, ear wax impaction and other conditions can cause or resemble vestibulitis (benign postional vertigo, vertiginous migraine, posterior circulation tia, focal seizure, menier's disease to name a few).

What are the only ear infections that cause dizziness labyrinthitis and vestibular neuritis?

Middle and Inner. By definition, anything behind the tympanic membrane can end up affecting balance, dizziness/ vertigo. Outer ear infection usually does not affect balance, but is very painful, and severe pain can cause dizziness.