ttc can be enough to drive you absolutely crazy! i would POAS as well - if it is bad news, it kind of makes you face up to it & spurs you into action for your next step. it isn't easy when it's negative but at least it's an answer!

if you're not 100% happy with what the doctor has said you should get a 2nd opinion or see a specialist. i also agree on the OPKs - it does help to know you're actually ovulating & when. as you say, there's such a small window for when you're fertile that even with regular sex, it is possible to miss the egg.

good luck, i hope you have some good news soon