every time i see a negative test i want to cry


my husband and i have been trying to have a baby for about 3 months now. i had the mirena removed several months ago and no luck yet. my husband keeps telling me he thinks he cant have kids, i have had 2 kids already so im pretty sure i can get pregnant but what if it is him? i dont know what im gonna do. ihad a baby for my sister due to cancer, she couldnt have babies...so i did it for her but what if i gave my last kid away and ill never be able to have another. there are so many scary thoughts i just needs some advice and support right now.