6 months is great!
Are you getting some exercise? Eating a fairly decent diet? I started feeling less tired all the time at about the 3-4 month mark, but that varies from person to person. If you were a really heavy drinker, it can take quite some time to feel really good again. Your body is healing - pretty normal to feel fatigue for a while. Getting a walk in every day, even a short one, really helped me get back to feeling good.
But if you really feel like the fatigue isn't getting better, I'd check with a doctor. Could be there's some underlying issue that needs to be addressed. Might be something as simple as a vitamin deficiency, or just that your diet needs some tweaking.