Lol quit or stay?

I got a new job recently and I'm not sure if I should keep it. In theory, it's the perfect; it pays weekly, gives consistent hours, and I have stable transportation to and from. The morale is also really good, but I cannot absorb any. What is mean by that is everyone will walk in smiling and generally having good attitudes, and I'm completely the opposite. Every time I so much as drive down the road to get to my building, I have the hugest urge to cry. And I do, but only a few tears, nothing dramatic. It happens every morning. My heart drops and my throat burns and i can't stop shaking. It all goes away though, after I come from my lunch. I used to have my desk decorated, but since then I've taken down the posters and stickers and have taken all of my books and other miscellaneous items back home because I couldn't look at them anymore. I don't even eat lunch because I have no energy nor feel a want to eat anymore. I feel like I should just grow up and get over it, but I don't want to keep feeling like this, especially every morning.