Constant Off Balance. Hb and low b12?

I have been having constant off balance for last five months now, most days this is severe in mornings​ upto 10am. And sometimes having in night also that time i feeling dry mouth , heaviness in head and tired face , fatigue, increased heart beat, and two times i felt i was faint in sleep but not sure. i visited ENT and Neurologist they prescribed medicines for vertigo, minere disease, nerve damage, but there's​ no improvement in my case. I did master health check up with ECG and MRI of head and came out everything normal , my blood sugar and Bp is normal and now last one month often feeling hotness in air when i exhale and i loss weight of 3kg in last one month. Finally i checked my Hemoglobin is 15, my b12 is 220 pg/mL so am confused is it possible to have normal normal hb and low b12 ? And am not strict vegan too ; please give your suggestions in my condition am fully nervous am going to die without diagnosed :(