Should I break up with him?

I met this guy through Craigslist (I know, I know) and we are now dating and have been for a couple of weeks. He treats me really well but he already says that he loves me. We almost broke up after a week because it was too much for me and I was ready to give up and he called and said he loved me and told me he was a good guy and everything. And in the moment I told him I loved him too but now I just say it because he says it first. He's not the guy I pictured dating: he is clingy, emotional, has a criminal record (lying exgirlfriend and I believe him), smokes, and is non Christian which is important to me. Maybe it seems obvious that I should break up with him, but is it? This is my first relationship (I am 23) and he says I'm just not used to being loved by someone. I feel smothered because he wants to call me everyday and see me every chance he gets but it's on summer and I just want to be with friends (we live closer together when I am at university). I dunno what to do: keep him around or just give up?