Period didn't come on the 5th as it normally does but hpt was negative most fertile on the 20 th had sex and no period could i testing too soon?

Could be: Conception, as defined by the generation of a fertilized ovum, occurs within day or so of the sex. However, it takes about 2-3 weeks for the embryo to make enough HCG to produce a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow 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.