Pregnant or what???

So here we are again...another month ttc. I am currently 3 days late. I took a digital hpt yesterday after drinking lots of water to get me going and it was negative. Like many of you, I want so bad to be pregnant with #2. I've had the tender breasts, backache, fatigue for over a week now which I know could be either or. Today would be day 31 of my cycle. The last three cycles have only been 28-29 days. I hate the waiting. What should I do? Any thoughts? Should I just consider it a missed period? It would be my first ever.