How are feeling generally? It's possible you didn't have a deficiency to start with. I went from being completely depressed, barely able to get out of bed to mostly functional (although still not quite as chirpy as I am in summer) when I started taking a vit d supplement in winter.

you might want to check on your Vitamin D receptivity. For example, I took a DNA test, and it indicated my Vitamin D receptors weren't as efficient as normal so I should take higher doses than other people.

I personally just felt a little sadder and lower energy in my first winter in a gloomy climate. The vitamin D just made me slightly more chipper and energetic.

I didn’t do a blood test pre vitamin D but tested recently and my levels look good, so my doc said to just keep on it.

Wouldn’t say the difference is transformative but it’s helpful.