I'm a new teacher with no friends in my department. Is this normal?

I am beginning my second year as a middle school teacher. I was a substitute teacher in this school for 4 years. For me, the hardest thing about teaching has had nothing to do with the kids. I have found that my grade level, and especially my department, are very "cliquish". Most seem to have established friendships. They do not include me and are not very willing to share teaching ideas with me either. I replaced a popular teacher that retired, and some of them seem to resent my being here, and have tried to undermine me at every opportunity.For the most part I don't have any trouble with the older teachers- except one in particular who is very rude to me. Perhaps they will never see me as being anything other than a substitute teacher.For example, i say good morning to her in the hallway and she doesn't even acknowledge me. And anytime I say something in a dept. meeting she has a snide remark to make about it. I love the kids i teach but I am fed up with the teachers. Any advice on what I can do to feel like I belong? Or to at least make the situation bearable? Even when I did observations and the practi internship prior to being hired, i found the department staff was very cold to me. My closest friends in the school are in the language department (a different department), so now I spend lunch in their break room. I know teaching can be a lonely profession and this is no help! What shocks me is the amount of gossip, back stabbing and pettiness. I have tried to be outgoing and friendly, but all I get back is nastiness. A friend suggested I keep my coworkers as that: just coworkers, and keep friendship to people I meet outside of work. The thing is, i don't' want to be as cold and unfriendly as the teachers in my department.