I can be kind of emotionless too. Psych meds + autism does a pretty good job at flattening me out. However, I generally find I have enough emotion to make life difficult interesting. I used to worry a lot about my apathy, like you, and wondered whether it was due to some kind of trauma. However, after a while, I just got on with things I guess. Not saying that's what you should do. But that's what happened with me.
I find socializing a lot helps (if you are into that). Listening to music helps too. So does making music, writing, and making art. Those things all help me feel more, I think. Might work for you, might not.