Negative test but still no period? 12 days late?

Typically I am very regular with my period. It usually starts the 28, but in Jan it started on the 20. I have yet to have a period for Feb and its march now. I have taken a test that came back negative. I took it on the 28 of Feb. Now if I was pregnant wouldn't I have gotten a positive on the 28. Anybody expierance this and how long did it take you to get a positive. My husband and I have NOT been trying to get pregnant and have been careful not to. I am just not what to think right now and I cant go to the doctor at this point due to the fact that I dont have insurance. I also have no pregnancy symptoms or period symptoms. Normally my face will break out and my boobs gets tender and I cramp with my period. With my first pregnancy it was about a month after I found out that any symptoms started and with my second it was a week before my period was due but I was also pregnant with twins. Any input would be appreciated.

Thanks