No period

Okay! I've been extremely cautious about my body. So I've been sexually active for a while now with protection. I've had my cycle last month and I was supposed to have mine 13 days again and it hasn't come. I've taking 2 pregnancy test and both were negative. I have been stressing out over numerous things. I'm really starting to get worried about me not stating. What should I do? Everyone keeps asking am i pregnant!!! I'm REALLY SCARED please help me