Don't force yourself to stick with something if you aren't getting the same enjoyment out of it. People who do that tend to end up hating the thing they used to like, looking for ways to convince themselves that it's always the shows fault, and just getting more frustrated trying to reignite that spark of their original passion.
My advice is take some time off, miss a season, and if you are participating in the fandom, take a break. Burnout happens, trying to force yourself to be passionate about something will likely just backfire and make you resent the show. Find something else to watch, read, play, or whatever, if you come back to it again later you might find that spark returning, or you may just find a comfortable nostalgia, maybe the show will never completely recapture your interest, but a little distance will help you look back on that entertainment as a good experience.
I've got a similar experience, I watched the episodes early on right when they came out on CW, now I just catch them whenever I've got time, I buy the seasons I like and don't stress out about it too much now. That initial fervor and spark almost never lasts forever with anything, sometimes the thing you liked changed, or maybe you changed, or life just got in the way, and the shows humor or world just isn't as appealing or relevant to you as when you first encountered it.
