Missed period

Samantha
Hi all,
So I'm two days late have a 28 day cycle always one day in or out, I have period type cramps, discharge. We only had intercourse 1 time during ovulation as he hasn't been well down with the flu. Anyway needless to say I'm tired but I think that's from the stress at work the last two days. I took a pregnancy test was negative. Any thoughts??