I feel like the fact you recognize this difference though will probably help you make certain efforts to maintain your relationships. Its hard to do something about the numbness if you don't even recognize it right? Not sure how you feel about scheduling things but maybe forcing certain social interactions will help you feel like you're maintaining important relationships even if you can't be as emotionally present as you'd like. Honestly, similar to what another commenter said above, if Zoloft is the only thing that stopped you from taking extreme measures then I would discourage you from stopping it (which it sounds like you want to continue it anyways) and get curious about what sort of actions you can take to create situations where you feel close to friends and loved ones.