Struggling to concieve

I have been tracking with opks when I will be fertile etc and they have all been positive every month for the past 6 months and my periods are on a cycle of 27 days like clock work. We have sex a lot during the fertile week but nothing is happening and my period has arrived again. My first pregnancy ended up in a emergency c section due to contracting sepsis and my husband was on antidepressants but stopped these 3 months ago could any of these things affect it?