Well, I beat Fallout 4 just now, and I must say the main quest line in the game is pretty fantastic. My head is also spinning at how different things could go if I had made different choices, which is fueling a massive urge to play it again. Of course having focused on the main storyline, I didn’t do much of anything else, so I basically still have 95% or so of the content to explore.
The plan is to start fresh, this time with a female, and push the main storyline only when it feels appropriate, heavily focusing on the major side arcs. Can’t wait!
Hardcore Casual 
I think I just finished it too. But the game doesn’t really give a good indication of it or anything either. Just seems to roll into faction quests. Pretty unsatisfying imo.
Really felt like the story was about to get started. Like you just went and met with House or finally found your Dad. The story felt like it hadn’t actually really started yet, but apparently that was it.
There is a fairly lengthy movie when you ‘beat’ it, did you see that?