, naucea, vomiting
on bending in your case can be due to following causes.
1] Ear problem: Benign paroxysmal positional vertigo[BPPV] ,Meniere's syndrome [Dizzines+tinnitus+vertigo], vestibular nerve
2] Neurological causes : Stroke
, brain lesion.
3] Structural cardiac and valvular diseases.
So consult neurologist
to rule out chances of stroke which is serious enough; doctor might advise you MRI/CT imaging.
Again you need to consult ENT specialist
to rule out above mentioned causes.
Cardiovascular causes will usually be associated with other symptoms like chest pain
, breathlessness on exertion; which is absent in your case. So this is likely to be least possibility.