I have been running a long, epic campaign for 2 years now. Players have come and gone over time; about half have stayed since the beginning.
But since they acquired a higher level and well as knowledge of game mechanics (5e), they constantly antagonize me, the DM, in my rulings. They try to bend the rules and abuse every aspect of game mechanic to "put me in my place" and beat the game.
I constantly find myself telling them they can't do something. For example, one player wants to abuse the Bag of Holding by using it as a vehicle, "All players get inside and a dominated eagle carries us". When I told them that the bag has a limited space, he was visibly outraged.
Another time, they were racing against the bad guys through the Teleport through Plants spell of the druid. I made one of the bad guys' many mages then simply use the teleport spell, the players got angry at me again.
It has gotten to the point where I am not willing to play D&D because they are trying to wrestwrestle all control from me as a DM, jumping and killing encounters I prepared with a lot of care and excitement (I put a lot of passion into my story, trying to keep it full with 3-dimensional characters, reoccurring themes, plot twists and dynamic relations. I even oil paint the most awesome moments that occur throughout the campaign).
I told them that the game can't be played if the DM can't have enough control to know what to prep, but then they argue that it can. I tell them that if the bad guys are a smart organization, of course I will let them outsmart the players, and I tell them that if they abuse the rules to do extreme things, why can't the Zhentarim do that too?
It's like they don't want to have me as a Dungeon Master and play my campaign, but they want me as a Dungeon Processor who runs their fantasies of unlimited power. And when I stop them, even with the best arguments, then I am the bad guy who is ruining their fun.
The problem though is, as sad as it might be, at this point of my life I've got nothing but D&D for fun. I really enjoywork a night-shift job, and work on my degree during the day. I am constantly broke, and D&D, writing stories, making adventures, and running the campaign is all I have, so I am quite anxious about breaking up the campaign, as any normal DM would have done by now. Because then I will be left with nothing, and all the heart I put a lot intoin to this campaign for the last 2 years will be dead in the water.
Is there anything I can do, or any suggested course of action to get my group back on track?