Could I Be Pregnant????

Last June my husband got a vasectomy. It was a mutual decision, but with extreme hesitance on my part. I wasn't ready to stop having kids, I truly felt/feel like we have one more child waiting for us. But I let him go through with the surgery anyways. He got the approval in october that he was "shooting blanks" and so I went off birth control. I am now going on 12 days late. My period is never more that 2-3 days late (except back in august when I was under severe stress of my parents divorce, it was 2 weeks late then). Anyways, is there any other reason for a period to be this late? I haven't been overly stressed lately, and I don't do extreme exercise. What could be going on? Is it possible I'm pregnant? I feel sometimes that I am because of mood swings, tired alot, and constantly want cheese covered tortillas chip or chocolate, but could it all just be in my head? I don't want to take a pregnanct test yet cause I don't want to get my hopes up, what do you think?