TTC and failing

We've been trying to conceive for 9 months and nothing. I'm so frustrated! Everyone around me is getting pregnant without even trying. I'm so sad! We've tracked and made love on all the right days, taken ovulation tests, why are we not pregnant?! I feel like we should take a break but my husband wants to keep trying. I'm just so tired of feeling like I'm letting him down and feeling so disappointed when I see that negative pregnancy test