I need help ttc #1...?

so i've been ttc #1 for about 6 almost 7 months now and i'm beginning to give up hope. my dh and i don't drink or smoke but we just can't seem to get pregnant. this may be tmi but i like to be on top alot could this be a reason why we're having no luck?? after we bd i lay on my back for about 15-20 min regardless of which position we use (again tmi i'm sorry) but when i get up it usually comes back out. i'm just really stressed and i want a baby so bad. i try not to think about it but it's really hard not to when everyone around me is pregnant. i just need some advice. fyi if you plan on answering this question in a rude way please refrain i can't stand negative nancy's kapeesh :)