Still fermenting

I started fermenting my wine 2 and a half weeks ago. I transfered it to the secondary about 1.5 weeks ago. The wine is still producing CO2 and i took the brix toda and they were at 5-6. I was wondering if this makes sense. Shouldn't the brix be down to zero at this point? It has been fermenting for 3 weeks already. Also i realized the wine is producing much less co2 then it was before. Should i maybe pitch more yeast into it? or can that cause problems to the wine? Thanks for the help.

Think primary 3 week, secondary for few month, then bottle. I'd let it sit for a while it won't hurt it.