If you were over-anxious in the past, and now you're able to take a step back and not feel overwhelmed by anxiety about world affairs, you may indeed feel "flat" as you adjust. Because once our brains are used to the hyperactivity of anxiety and settle out, it takes time to set a new baseline, and in the interim it can feel depressing. But that's not the same as not caring about anything. If it's that things that triggered you are being resolved (politics or whatever you were super-passionate about), you'll still find you can make a difference and empathize, but maybe not be consumed by it.

So, if you don't care about anyone or anything and wouldn't help at all, that's apathy. But if you settle into a place of reasonable balance where you can choose your causes but not burn out, and do what you find meaningful, that's what I'd call healthy. Maybe you can talk about it with your T and be patient with yourself and see....

have you been feeling this way long, was it triggered by something suddenly, have you talked about it with your T at all yet?