HELP! please.

Ok first of all I haven't had AF in two months had what I think may be implantation 7 days ago but no BFP yet I'm 2 days into my next due AF and want to start taking isoflavones I'm taking met at the moment but want to try this.. My questions are: 
1. Could I have got pregnant even though I've had no AF?
2. If I am pregnant and take the isoflavones will it hurt the baby or cause miscarriage? 
(I plan to take isoflavones days 3 - 7 of my expected cycle) 
3. How long after suspected implantation would I have got a positive??
4. Will the isoflavones still work if I start without AF?? 
5. Will it bring on AF?