@aperson,
The first thing that comes to my mind, is that maybe you're in the wrong course of study. If you're losing enthusiasm and are bored, or think that it's not important and won't make a contribution in terms of life in general, maybe you should do something else that is more practical which would enable you to observe a product or result and see something achieved or accomplished apart and aside from an A* on a paper - because really - as you said, if it came so easily and it's no longer meaningful to you, why do it anymore?
I was talking to a guy today who was initially an engineer, but even after graduating and working in the field, decided it was worth his time and effort to make a change, and now he's taking a course in surveyance and he's done water surveying and now he's doing surveying from the air (learning in a practical course right now). He's going to be surveying a small island 400 miles off the coast of Madagascar in a couple of weeks from the air.
That sounds pretty interesting to me. And I would never have known that was a course of study. I guess what I'm saying is that there are so many options open to you at this point- don't quit because you don't like what you first chose - choose something else if necessary.
I think the advice about physical exertion is a good one. And maybe you could generalize that to work. Maybe you should do some physical work that would result in a finished product. I know when I was in school, in the summers I always worked on a farm or in a garden. I loved being outside, I loved the sense of accomplishment readily visible by the weeded garden or the baskets or harvested vegetables, and it was a good and needed departure from my usual activities of reading and writing papers and thinking.
I'd also advise you to find something fun to do as David advised. And one of the most fun and rewarding ways I've found to spend my time is with children or people who are less intellectually able than I am- because I just find them so refreshing and funny- and again, so appreciative of any time or effort spent on their behalf. And you can learn so much from their views and perceptions on life that tend to be so different from your own or the more 'normally' or 'highly' intelligent people you usually spend time with.
In terms of connecting - I'll always remember what someone said to me when I was about your age (I'm guessing) and I was complaining about a friend to him, he said - 'You can't control what kind of friend anyone is to you, you can only control what kind of friend you are to them'.
That made me realize - maybe I wasn't being the best friend I could be. And since then, I've always just made a point to be the best friend to anyone I wanted as a friend that I could possibly be- without always worrying about what they were giving me.
And my connections since then have been close and tight and wonderful- with ALL kinds of people.
It's so much more interesting to have some connections with people who experience things differently than you do, than to always be with people who process the world and experience it just like you do- in other words, other smart people.
Sometimes I think intelligence, especially as some sort of goal and as any sort of be -all and end- all, is overrated.