if you luteal phase (O to AF) is less than 10 days, it is deemed too short to be successful in holding a pregnancy. i would suggest tracking ovulation signs using a program like fertility friend, or with OPK's for a couple of months, and if O is late each cycle and your luteal phase is short go and speak to your Gp about your concerns

in a "normal" healthy couple, it's not unusual to take up to 12 months to conceive, so you may find you get resistance from your GP if you go in sooner - hence me suggesting you track your cycles and go in armed with "evidence" that your luteal phase is not long enough to help you in conceiving