Hi My Name Is Kari Castle And I Was Suppose

Hi my name is Kari castle and I was suppose to start my new pack of birth control pills on dec11th but my pharmacist hasn't had it in yet so I haven't took my pills since then and I haven't started my period for this month yet. I took a plan b and a pregnancy test on dec 27th and it was negative should I take another one or what should I do ? Could it be because I missed almost a month worth of pills and I usually start my period 28 days after I start my new pack and I haven't had any bleeding or pain