What you're describing could be vertigo, especially because you experienced a sudden sensation of the surroundings spinning with imbalance. However, dizziness can have several causes like dehydration,
vitamin deficiencies, anemia, low BP, anxiety, or inner-ear problems, so it cannot be diagnosed from symptoms alone.
If the spinning episodes are brief and particularly triggered by turning your head, getting out of bed, looking up/down or changing position, BPPV (an inner-ear balance problem) is one possibility.
Your
B12/
Vitamin D deficiency and anxiety may contribute to feeling tired, light-headed or unsteady, but they should not automatically be assumed to be the cause of true spinning vertigo. A normal ECG and
thyroid test are reassuring but do not evaluate the balance system.
I would recommend an in-person examination, including BP (including postural BP), neurological examination, gait/balance assessment and ear examination. Your doctor can then decide whether an ENT/neurology evaluation or further testing is needed.
Next Steps
For now, stay hydrated, get up slowly, avoid sudden neck movements and do not drive while dizzy.
Health Tips
Seek emergency care immediately if the dizziness/imbalance is sudden and persistent or is accompanied by difficulty speaking, facial drooping, one-sided weakness/numbness, double/loss of vision, severe headache, inability to walk properly, or repeated vomiting.