Missed period and late

So my last period was October 30th. I was due November 27th but didn't even get a drop of my period. That was my last week of the birth control pack and I didn't start a new one (currently on nothing) due to it causing extreme cystic acne along my jaw line. I took 2 tests and both read negative. I was due again on Christmas Day and haven't gotten it yet again. Took a test today and came out negative. I've had very very very mild cramps for a few days now but no bleeding or spotting of any kind. Does anyone have any advice or suggestions as to what this is....?