How will I know if I have meniere's disease?

Ear exam. Your history plus ENT examination plus hearing tests usually suffice to answer the question. See an ENT doctor.
You may not? This is a diagnosis that should be made by your pcp or an ENT or neurologist. The key feature is ringing in the ears, cricket sounds in the ear and other associated symptoms. Get a proper diagnosis. Some testing and hearing evaluation may be necessary.