question for those who have already been pregnant

Hi ladies 
I was wondering if any of you ladies experienced changes in your cervical discharge BEFORE missing your period? I am due to start next Tuesday but yesterday I wiped and my discharge almost looked like snot. Really thick and not really clear more yellow (but no blood). Yesterday and today I have had way more discharge than usual and it just looks different. More white today. I have also been constipated and my stomach has been cramping but wasn't sure if that was just from the constipation.