My cervix is high, hard, and closed. as well as 3 days late on period. took a at home pregnancy test, and came out negative. what does this mean?

Re do test: If you had sex since your last period, it would be prudent to repeat the test in 4-5 days, unless you get a period by then. Use first morning urine and follow the instructions for the test carefully. If you do not wish to be pregnant, use contraception all the time, every time. You may consider implanted contraceptive, or IUD. Practice safe sex. Get HPV vaccine.