I agree with Missy, if you loosing some of that boxing-jive you need to loosen up. Training can be a real grind at times, that's why there is something called "fun" Go clubbing, grab some buds, some drinks and just lose yourself. The best antidote for the blues is all-out fun!

As for motivation, look up the great fighters. Last time I looked, I got to understand pugs that I previously knew little about, got to know what kind of school of hard knocks they went through. There's so many larger-than-life folks out there, all you gotta do is look. And my god, if you can't find inspiration in the living, how the hell can you be inspired about life.
Rocky Marciano, Julio Cezar Chavez, Jersey Joe Walcott are the best in my book.

I wouldn't go as far as to say drop it, but if there's something that you'd love to do more, go for it. For me there's nothing more fun that to slip on a pair a gloves, it makes me feel like a different person, and boxing is where I find my groove. It could be your gym, you if all else fails you can check out other gyms to find a fit. Get a coach that'll motivate you, show you the ropes, and can show you what you got and what ya gotta do.

Hows the atmosphere at the gym, (sparring partners, skull practice, Equipment)