Danni, don't panic or get too stressed about it (I know, easier said than done!). As Bethany said, a luteal phase defect IS treatable if that is in fact what you have. You never know, your cycle may adjust itself and you will have a longer luteal phase. And, as it has been pointed out, it's definitely treatable if it does turn out to be a issue with you TTC.
Let us know how you go on Tuesday if you get to mention it to your Dr.