what's going on with me?!

Marissa • Mommy to one little boy and one little girl 💕💙💕
First off I want to let you all know that I have been ttc for a year and 2 months..me and my SO have BD every other day this month... I'm on CD 29 I usually have 21 day cycles.. I have tested already and I have gotten all negatives I have used 3 brands, pink dye and blue dye, the lines and the word (not pregnant).. I tracked my o and that was on the 9th of march. I haven't been stressing or excessive work out this month so that can't be why the witch hasn't shown... i have taken iron pills this month because I have been low on iron... is there anyway that the iron could effect me getting pregnant or not starting my period.