For the longest time I was emotionless. Partly this was because I actively cultivated this non-attached and disengaged state for years. I was also depressed because my life goal (truth realization) had seemingly been frustrated by DP/DR. My value system was upside down and I was withdrawn from the "real world" and social connection. Ironically, I had a panic attack about my lack of emotion when I felt I my mind had been completely fried and blown up by anxiety. Then the floodgates of emotion opened, and DR lifted for a while.
Anxiety can be unconscious, bubbling beneath the surface. That's why even when conscious anxiety passes and you're in recovery, you can still experience DP/DR for a while, and it can emerge at random moments. [EDIT: I believe you do need to start feeling again to fully recover. Suppressing emotions can slow recovery and halt it in extreme cases.]
Your brain has been so overwhelmed with stress, traumatized even, that your brain said 'I don't give an f anymore' and dissociated. It takes some effort to break through that wall and reconnect with your emotions. You need to see that reality is safe and meaningful and that you are strong, and work to draw out your feelings and re-associate them with reality.
Anxiety isn't bad, and if you suppress it, you also sacrifice the positive feelings and shrink from being fully alive. Face real world situations that might stir up your natural emotions. Does anything at all make you feel even a trace of emotion? If so, you need more of that.
And when you don't feel anything at all you're doomed? I can't feel anxiety anymore..