I'm sorry you're having so much trouble. Are you charting at all? That in itself could give you a lot of information. You may not be ovulating, you could have a luteal phase defect, or several other possibilities. What are your cycles typically like? Very irregular or heavy? Abnormally painful? I'm 26 with PCOS and adenomyosis, both of which cause infertility. You can work around them if you know you have them though.
Bleeding heavily after having a baby isn't necessarily a bad thing. Some women stop bleeding very quickly and it never gets that heavy while others will have fairly heavy bleeding for months. Like many things with the female body you have to take it on a case by case by case basis.
Have you talked to your doctor about TTC? At this point since you haven't been preventing for roughly 4 years any decent doctor would begin tests sooner rather than later to get you some answers.
You can find a list of the most common abbreviations at the bottom of this post.
http://www.justmommies.com/forums/f2...eviations.html
Hope this helps!