Maybe a different perspective for you. I used to work with a guy who always seemed happy. Its not that he was happy at work, he was just happy in general. He wasn't exactly the most motivated or proficient at his job either. Pretty low responsibility, low pay, but got sh*t on quite a bit. None of it mattered.
On the other hand, I loved my job when I first started, but grew to really resent it. I had a lot of responsibility which I thrived in, but got crapped on more than was reasonable or fair. All the things I did above and beyond expectations were taken for granted. I absolutely hated it and I hated the fact that I couldn't find happiness at work anymore. And that eventually became something that I took home with me as well.
After doing some soul searching, I decided what it was that made that other guy so happy. He didn't give a damn about work. He had happiness at home and he just went to work to do what he needed to do, so he could afford the things that made him happy at home. Simplistic, but it works.
As for me, I tried but I knew I couldn't separate myself from work by that much when I had already been so involved in everything. If I did, I would have to really compromise everything I had worked to establish myself as a professional at that place, and I wasn't willing to take that hit to my integrity. So for me and my situation, the answer was to leave and start over at a new job. I now have a great job, which I can NOT complain about. Pay is great, people are professional and intelligent, minimal stress, and I even have normal working hours as opposed to rotating shift work.
Just a couple of thoughts for you. But as everyone else has commented, don't jump too quickly. Do your research and make a good decision. You have a job which is presumably covering all of your needs right now, it would suck to lose that to something you resent even more.