Help?

❤️ bree ❤️
I was 14 days late on my period when I went for a blood pregnancy test and it came back negative. Well, that was only 7 days after my last u protected sex. Some people are telling me that's too soon to get the test done and others are saying it's not. Well, now I'm 21 days late on my period and nothing but sore breasts (which honestly happens a lot) but idk what to think. 
I know I had stomach pains and loose stools due to something I ate but that's gone now. No other symptoms. Home pregnancy test came back negative but all of my moms read negative too for all 4 of her children.