I want answers

So , I never ever get cramps before I get on my period . And 2 days ago , I threw up had headaches and cramps very bad cramps . And my period hasn't came , I'm supposed to get it in a day according to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> I just found it weird that I got cramps so bad like that .