missing period

been TTC for about 1 year granted me & my husband have had the ' if it happen it happens ' for about 2 1/2 years .... my cycles have been pretty regular ranging between 28 - 30 day cycles which is normal for me ... i'm currently on cycle day 35 which means in about 4 days late we did have baby dance during my ovulation week & peak day ... ive had sore/ tender nipples , fatigue , nausea , headache , a slight cold , and been emotional / mood swings ..i took a pregnancy test this morning & it was negative .. would love to hear some opinions on this ...