Can anyone help with my questions

Jemma • Been trying since last year had a miscarriage in December :( but trying to conceive again
I've had two miscarriages does that mean I will have a third or could I go on to have a healthy baby or could I have something wrong with me where I can get pregnant but can't carry?
I've never worked out when I have conceived properly so when glow says fertile days would you just bed them days or all the way to your period?