My September Menstural Was Like Every Month Regular In The

My September menstural was like every month regular in the beginig of the month (can't remember exact day) October and November were like 2-3 days late making it more right before the 10th. Now this month (December) it's the 20th and I have yet to get a menstural. So I took 2 clear blue choice pregancy tests (they are what I used last time I was pregnant and missed my period, and was positive, so I can trust this high end drug store pregnancy test) so I take a test today first thing in the morning, well I took 2 and both negative. I have had mild cramping the past 2 days but it could have been linked to the diherrah and constipation I have had the past 2 days. No nausea or morning sickness, I do feel like "fuller" in my uterus if that makes sense. By fuller I don't mean I look fuller I just feel fuller down there if that makes sense..but I think that might all be in my head. I have not had un protected sex, me and my partner always wear condoms. So first thing Monday(today is Saturday) I will call my gyno and make a app doe Friday so a week away. And if I do get my menstural before my app (gives myself a week to really see if I get it or not) if I do get it before I will just cancel my app. But in the mean time, do I sound pregnant or just irregular?