Dizziness, vertigo, loss of balance, nausea could happen also because of other reasons: dehydration, sinus problems, ear problems, not eating properly, virus, stress, etc. etc.
But of course, you decide when to go to the Dr. It could be a serious reason or it could be nothing serious.
My father died because of a brain tumours at 47. He was operated in 1989 because of 2 small tumours. Then in 2003 he died because of 2 other small tumours that formed along the years and the Dr. couldn't reach them.
My aunt (35) and my neighbour (32) also died because of brain tumour. They had the dizziness and the headaches. But my father found out because he couldn't see with the right eye, he went to the ophtalmologist which saw something was wrong and then sent my father to the hospital for further investigations and he found out he had 2 brain tumours. He never said he had headache, but he complained that he was dizzy.
So, really, if you feel that something is wrong, just go to the Dr. You may say it is just dehydration or winter or sinus or ears but go. You need treatment for Sinusitis also. I've had Sinusitis and Otitis all of my childhood and always had to be on treatment. My stomach is destroyed now because of the antibiotics. But I hope now there are other treatments.
Press the Dr. for investigations. Change Dr. if you have the feeling that he is not taking you seriously.
Someone I knew, was complaining of an ache in her calf, she went to the Dr., the Dr said she needs Mg and 3 days after the Dr. visit she died in front of her kids and husband because of a blood clot. She was 35. And my mother complained about different pains, she went to the Dr. , he told her is just Menopause and she died few months after because of cervical cancer. She was 52.
In my case, I went to the Hospital, here, with extreme dizziness, 2 times- Dec. last year- the Dr. said I have a Virus but doesn't know what kind of Virus. And this April, because of stroke like symptoms and they did MRI, CT scan, lumbar punction (that hurts!!!!) , they only said I have an infection in the blood but they don't see anything wrong with me. It could be that I have a Virus that keeps nagging me. They first said I had a stroke (because I couldn't move my left arm and slurry speech; no such thing was seen at MRI) and then said I have MS.