A Vit D level of 12 is a clear deficiency and can absolutely cause fatigue, low mood, muscle weakness, and low energy.
At 229, you're in the borderline range for
B12. Some people feel symptoms at this level like fatigue, brain fog, tingling in hands/feet, low mood and weakness.
Next Steps
You should take
Vitamin D supplementation.
Typical treatment (confirm with your doctor):
60,000 IU once weekly for 6-8 weeks then
1,000-2,000 IU daily maintenance
Also:
15-20 minutes of sunlight exposure (arms/legs exposed).
Take Vitamin D with a fatty meal for better absorption.
It would be reasonable to supplement
B12.
Common options:
Oral methylcobalamin 1000 mcg daily OR
If symptomatic, some doctors give B12 injections.
Recheck in 8–12 weeks.
Health Tips
Before starting high-dose
Vitamin D, confirm:
No
kidney stones
No high
calcium levels