Late period—not sure if I’m pregnant

My last period was much shorter than normal—only 3 days and it’s normally 5. This month, I’m late by 12 days so far and I took a test on day 7, 10, and this morning. All tests were negative. I’m never this late with a period. However, I’ve been having mild cramps and sleeping more than usual as if my period were coming and yet it hasn’t. Very worried. Has this happened to anyone before?