For my first three pregnancies I was taking folate but I miscarried all three very early.

My fourth pregnancy I wasn't taking it because we weren't trying but I started taking it at 3 weeks (so one week after O) because I suspected I was pregnant.

Once I knew I was pregnant I switched to the Cenovis Pregnancy vitamins which contain fish oil (for bubs eye and brain development). My diet was not the best before pregnancy and got worse during it as I had a small appetite and wouldn't eat a lot of things so it was necessary for me to get vitamins from somewhere. They only cost around $15 for 30 days supply. They contain vitamins to help with morning sickness (I never had any at all, don't know if the vitamins helped with that, could've just been luck). They have zinc in them which supports your immune system - I never got a cold or any type of infection - not even thrush throughout the pregnancy. It also has iodine in it for bubs brain development (new studies show most women are iodine deficient because we don't eat enough iodised salt). Also has B vits and iron to support your energy levels. I managed to work til a couple of days short of 37 weeks (full time), a lot of women half my age don't manage to do that. I have no idea if it was my vitamin intake that helped me have such an easy pregnancy but I can't explain it any other way.

As for your question about symptoms. I started to suspect I was pregnant as I had bleeding gums and a stuffy nose from 3 weeks onwards. I get these symptoms when I am pregnant - they are the first things I notice. I was still temping so I also noticed a two day temp drop at 3 weeks. I was not at all surprised to find myself with a positive when I tested a few days later.