I think I understand what you mean. I was on ADs (Effexor XR) for nearly 10 years, and they seemed to help with the depression. But I wondered if it was really worth it as I just felt numb all the time, like I was on auto-pilot or something. And like you, I was still able to go out and see friends and laugh and joke with them and seem like a more sociable person, but I could quite happily have stared at a wall for hours. Sometimes I felt like I wanted to be the way I was before, because at least I was feeling something then. All I wanted was to be like the other people in my life who seemed to have no cares in the world.
I have been off meds for 2 years now, my depression has gone and Im doing really well, but I have very few memories of those 10 years. It feels like I was asleep the whole time I was on them and then woke up into a world that I didnt understand and couldnt deal with on an emotional level without medication. There are still times now that I have to stop and think whether a memory I have actually happened or not. So, I understand how you feel in that respect. Im just not sure I can answer your questions. Have you asked your doctor about it? Is this medication right for you? Have you given your body enough time to adjust? Do you look after yourself; eat properly, sleep well etc? Dealing with this can be such a rollercoaster that sometimes you are constantly exhausted both emotionally and physically and you are too tired to get excited about anything. Do you have hobbies that you can set goals for and work to achieve them; going to the gym, playing music, writing etc? Sorry, Im just throwing ideas around here.
I so wish that I had the solutions for you; all I can suggest is to continue to do the things that do make you laugh and that bring some emotion into your life. Its a horrible 'feeling' not to feel anything, and to be self-aware enough to know that's what's happening. I really hope that you can get through it, and if I can help in any other way, just ask.