Note that there are several other causes of attacks of vertigo that may be inappropriately labeled Meniere's, such as viral labyrinthitis, hypoglycemia, irregular heart beat and sometimes benign positional vertigo, to name a few.
If the Meniere's affected ear is your left, the ringing tinnitus you describe is likely secondary to the damage in that ear. The tinnitus usually remains stable between attacks of Meniere's but may change with subsequent episodes. I do not know what the thumping sound is you perceive. I would recommend a hearing test by a licensed audiologist and evaluation by an ear, nose and throat specialist for this new symptom you are experiencing.