2 Weeks Late, Negative PT Result

My husband and I have been trying to conceived. Last period ko was January 11. Expected the next one last Feb 8 kaso hindi ako dinadatnan until now. Nag PT ako last Wed and kanina pag gising pero negative ang result. I'm not sure if I'm pregnant or what. Any insights po? Btw, simula nung Sunday nakaexperience ako ng cramps and lower back pain. And then now parang nag spotting ako.