Its been a whole month with no period and still negative results

For the whole month of December 2018 No period . Months before i always had a period. So for last month with no period was scary. Today I’m 27 days late finally took a test mind you I’ve been so busy working. I work overnights as a stocker for Walmart. The results of tests are both negatives. I was told to take them in the morning. I actually took test just now. Meaning i would have to start over. Which this is would be my first everything so keep in mind it’s scary. I don’t know what to do.