Please help

Shaydi • :) baby dust to you all
I'm so confused and very sad:(?I took a pregnancy test just a little while ago and it was negative :( also I took one 2 days ago and it was also negative and today is when it implants. I was very sure of myself that I would get pregnant this month because I was fertile on the 28th threw the 1st and had a positive OPK on the 29th,31st @3ed so my fiancé and I had intercourse on the 29th,30th,1st,2ed @ 4th so I really don't understand why the test didn't come back positive :(