-Kind of a long story ....opinions ?

I've been with my bf for 5 years ...ever since we met we have been having unprotected sex, for the first 3 years of being together we tried having a baby but I would never end up pregnant..., after the 3 years I went to the clinic to get my blood work done and the Dr told me I was anemic and that I had to take iron pills. 2-3 weeks after I started taking them I ended up pregnant , I don't know if I got pregnant bc of the iron pills ? or this dietary drops that I was also taking..., my bf wants to have another baby and he keeps on telling me to go to the Dr so that I can get the iron pills again but I'm not sure if that had anything to do with it.