If you just have enough energy to work through the roughest and most painful areas of your emotions you might break through to higher levels of functioning. Because I know from experience that when you feel apathy you don't even feel like working on the solutions to your apathy. It's a circle, and you can get out of it if you have enough energy to do the things you need to do to get out of it. You probably know there are many possible methods of healing, but you just have to have the energy to do them. So find a way to increase your energy.
Another point, is that in some clinical illnesses like clinical depression, the depression is so bad that it affects your chemistry, and then hands you apathy on a golden platter as if you needed the precious gift.
In some cases people definitely need antidepressants. But I wouldn't go with that in a hurry, there are many alternatives to boosting your energy. Boosting your energy is what I would look at first. I don't claim to know much about unblocking energy in the body, but it does make sense that blocked energy can cause a lack of energy, or apathy. So I would look at unblocking your energy. One of the most powerful creative energy sources in us as human beings is our sexuality, so if you are having problems in this area I would look at healing for this area.
I'm sure many would recommend Spring Forest Qigong for unblocking energy.
Keep trying, and never give up!