30.8 ng/ml

My blood work came back as 30.8 ng/nl. Doctor said “everything looks good!”. I want to be in optimal levels not on the low end of whatever acceptable is considered to them. I’m SO fatigued. I went to get my D levels up to see if it helps. I started taking 5,000 icu with K a few days ago, but I’m wondering if I should take more than that. Is 5,000 enough for my situation? Any advice is welcome. 🙏