Pretty much. The game is VERY side quest oriented. That's the bread and butter of it besides the actual gameplay, dialogue, combat and exploring. Blowing up megaton just took away like ~10+ side quests and a potential house and multiple useful stores. Tenpenny Towers just doesn't compare. The game is huge though so I wouldn't say you ruined it or anything. And it takes a while to start really rolling. At a low level you're food out there. Until you get better guns, more health, some caps and stimpacks you gonna be going back and forth to hubs (the main one of which you destroyed)
Just start talking to people or head to rivet city.