From all your responses below, it sounds like you are pretty much ready to leave. Although at first I agreed with many of the responses below that recommended you "stick it out" even longer, judging from your reaction, it appears that you want to leave and you are financially prepared with savings at the ready. In that case, sometimes, inaction is action so why not put some feelers out for possibilities? Just because you're looking doesn't mean you will quit. Evaluating your options may help you decide that what you have now isn't so bad after all or may lead to a new adventure.

It doesn't seem like it would be irresponsible to just look around for options.

My first job was paying a good amount of money and I also went to graduate school and worked hard to prepare for the job but looking back, I was lethargic and quite bored. Because it was my first job, I thought all jobs just felt that way. People would say "it's called 'work' for a reason - it's not supposed to be fun" so I accepted that because I had no other experience to compare against. Now I have the perspective to know that it was a boring job that happened to pay well but I love what I do now and it doesn't even compare in terms of fulfillment and joy.