Pictures and notes on your care would help get diagnosis from members.

Greening is taking its toll on a lot of citrus here in FL. Definitely pictures would help.

Here are some pictures of my little tree. It's been in the ground about 3 years I guess, I saw some new growth this morning, but the rest of the tree looks pretty bad I think. I appreciate any advice. Thanks!

I have a poor little lemon tree struggling like that too. Pretty sure it's greening, and then a cascade of other maladies follow. Lemons seem highly susceptible.

My impression from the photo is that the plant may not be happy in that soil. It appears to be sandy and lacking nutrients - common Florida soil issue. Experts will say to not mulch a citrus tree, but if fertilizing alone isn't letting that tree thrive - well...Could be greening, if you find that to be so, I guess that plants a goner. but if you try to save it, perhaps some compost or natural mulch will eventually break down and begin to build a ferile soil. Keep in mind that citrus has roots very close to the surface and a thick layer of mulch could suffocate them. Best luck.

Looks like citrus greening to me.