why is it so hard :(

me and my partner decided last august to finally try, he already has a 4 year old from a previous relationship and i’ve been in the picture 2 years. ever since we have tried it’s been negatives, but then my period is late every few times and i get excited but it comes on the last day :( it upsets me as i’ve always been scared of being infertile and now it’s just not happening it makes me super upset. we know so many people with kids already who are horrid to them who are now having new babies and i just think it’s unfair on how people who don’t deserve their amazing child in the first place are having a new baby and it’s just not happening for us