It's only 3 days....

So 13 days DPO and I have been having  mild nausea for almost a week, gassy compared to normal,slight pressure/cramping in lower abdomen may be due to gas, had some brownish discharge when I wiped 3 days ago then nothing since. AF is supposed to be here tues but I cannot stop thinking about it. Why is it so hard to wait to see if AF comes vs testing over and over like I see people do on here. This is my first month tracking everything and only 2nd month off BC and I cannot stop thinking about it.