Moriarty's web wasn't that big in fact, so... Most part of those two years away Sherlock actually had adventures, cases for fun and such... high as a kite the whole time, and fucking around just to get more drugs since he didn't have that much money. He was virgin before that and sober for a long time, but, oh, well.

So yeah, Sherlock had had drugs, sex for drugs, adventures, while John was mourning him.

Afterwards Sherlock lies about being busy eliminating Moriarty's web during his two years away. John even forgives his fake suicide, even though it takes awhile to forgive. But then John learns the truth and Sherlock can go fuck himself for all he cares.

Angst, please.