Hello Liv, and a warm welcome to the site.
When you try and explain to anybody that you feel disconnected, alone and empty, then those you may tell do the opposite to you, which only makes you feel cut off even more, because at this point it doesn't matter what they say about all the friends and the lifestyle you have, it means nothing, because you feel the opposite.
There may be no specific reason why this may happen, but any mental illness is similar to doing a job but it's not as good as you would normally do it or alternatively you don't have the energy to want to begin, so all of this will overpower you and why, well you aren't sure why, it just happens.
I'm not a doctor to say this, but I can suggest from my own experience, and that this feeling won't go away by itself, although you may believe it's not as bad as originally, but the problem may not have been solved, just pushed away, so are you able to visit your doctor and please don't be afraid, they look after people and understand your position.
Ask them about the 'mental health plan' this allows Medicare to pay for 10 sessions with a psych, this will get the ball rolling.
Take good care of yourself.