Can Vaginal Infections Prevent The Occurrence Of Pregnancy?

Hi for 2-3 months now me and my partner have been having sex without condoms for we are trying to have a baby, every time he ejaculates inside me I feel sick shortly after and from that point untill I get my period I have feel pregnant, yet I always get my period I ve recently started taking metronidazole for a vaginal infectio I suspect I ve had for a few months now can this infection be why I cannot conceive ?