Friends... It'll happen

I get so frustrated with my friends that tell me it'll happen, I know they're just trying to be nice and supportive but the ones that have kids were all unplanned pregnancies so they really have no idea what it feels like. Anyone else have this issue? How'd you talk to them? I don't think I can smile and say i know it will, or toss in the old it's not that easy for everyone. Ttc for 9 months now. It'd be different if I'd bring it up in conversation but I don't as we all know it's not something we want to be reminded of. Thanks!