Get it more light.

FataMorgana

Also give it a much larger pot - those roots will be having the breath squashed out of them, and they won't be able to absorb any of the nutrients from what little soil is left inside the small pot. You could also consider removing those suckers, which right now are sucking the life out of their mother.

I have grown a lot of Curry leaf plants in containers. In zone 7a I manage to keep them healthy by shuttling them in and out of doors depending on the weather. They need as much sun as possible. Keep them outdoors when the minimum temperature is above 50 degrees. Indoors if there is lower minimum temps or a lot of wind chill. In summer they do great, in winter they just kind of hang on. I get scale insect in the winter which is difficult but does respond to a spray of insecticidal soap. I do not specifically fertilize them but I pot them in Miracle Gro potting mix in as large a pot as I can use. I just top them up with the potting mix from time to time and that seems to replenish some nutrients. Hope this helps!