We can't tell you why you haven't gotten your period yet.
It could be pregnancy, but if you've gotten 3 negative tests,
then .I think it's safe to say that you aren't pregnant.
But that means there's another problem at hand,
so you really need to call your gyno &see what's up.
&.Ask her about getting on birth control-
&use a condom every (every every every) single time.
If you don't want a baby, you don't need to take chances.
Good luck to you.