Niacinamide questions

I started taking 250 mg/day niacinamide hoping to regain some energy, which I've lost a lot of from being sick. I'm also taking a non-methylated B-complex which contains 108 mg (8% inositol hexaniacinate).

1. Is 350 mg enough? Too much?

2. How long should it take to start feeling the effects?

3. Do I need to worry about it draining methyl groups? I do eat a good deal of foods that boost methylation.

4. Do I need to cycle it?