I think you want a broad support system - those that have known & loved you for awhile, and some new people, who have been through a transplant. The old friends may not understand transplant specific things but they care about you. The new friends can help a bit with the transplant specific stuff.
Your medical team should also be a part of your support system. Let them know you are experiencing depression, anxiety, impatience, or whatever your emotions are. The meds are powerful, especially at first, and sometimes they need to be lowered or switched. They can definitely add to depression, because they are, in fact, designed to depress our system, so as not to attack our new organs.