Does stress make meniere's symptoms worse?  

Meniere's syndrome. Yes, stress and other factors can make meniere's worse. A good ENT can help. Janet callahan at mgh in boston is an expert in treating this.
It can. I have found stress to influence many medical conditions. See if you can make a stress inventory of everything you can think of (both good and bad) in your life that add stress burden. Give an approximate value for each item. Then try and figure what your stress limit is. If your stress load for the day will reach or exceed that limit, that might be a day when your meniere's is worsened by stress.