I was a fan as a kid, but as I got older, Trek lost a lot for me -- after Khan, it was really kitch -- especially bringing Spock back. That was it for me. I watched TNG because it was the only real sci-fi at the time.
I didn't watch DS9 or Voyager because overall, Bab 5 was better sotrytelling. My interest in sci-fi has pretty much waned. Not much you can do about it. I just embrace my new interests.
I've gained an interest in the universe as a RPG, but I don't bother much with canon because...well, it's fiction, it's our game, we do what we want.
The point? Don't fight it. If you're losing interest, find something else to charge yourself on.
"War is an ugly thing but not the ugliest of things; the decayed and degraded state of moral and patriotic feelings which thinks that nothing is worth war is much worse. A man who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself."
John Stuart Mill