might be pregnant?

Alexa • Love and live ❤️
Hey so quick question for the females on here.. so I'm 21 days late for my period I took various home tests and a blood test at the doc about two days ago. They all were negative. But my period still isn't here ? Any suggestions as to what's going on? I'm not trying for a baby me and my man are both military so we aren't planning one now. I'm not on birth control (I know I should be) and I'm not taking any medication that could interfere with my cycle.  ??? Help ???