No period yet 😕

Hi ladies I'm new here... Well I'm just kind of concern about my period I haven't gotten it for a whole year already. I took several pregnancy test and they all came back negative!! A little disappointed 😢 I have gone to the doctors and no answer yet they just tell me I'm stress which I know I'm not. I also been having really bad cramps here and there but no period. I've also notice that when I sleep in my stomach I feel something move and is so uncomfortable. I get nauseous as well but I'm not pregnant!? Does anyone have any helpful advice for me please. I would really appreciate it.