Just got off the pill, missed period..please read?

So i was on yasmin for about 5 months but in the fifth month of the pack i missed a lot of pills so, i decided to just get off the pills all together ( i stopped taking it in the second week of the pack) this was towards the end of november..... i did experience some bleeding a week after i missed the pills it was very very light my period was due for december 4th but it did not come down. it is now dec.22 and still no period...is this normal or is there a chance i could be pregnant? i took a test 2 days ago and it came out negative