Thin uterine lining? Scarring? Something else?

I've been pregnant 7 times (4 births, 3 m/c).  Two of the pregnancies were "unplanned".  The other five I conceived *immediately*; I mean, on the very first month of trying.  

I had a d&c in Dec (my first).  We started ttc again right away. I have had 5 normal cyvcles since then.  I am charting my temps, and seem to be ovulating.  Why am I not getting pregnant??  BTW, genetic testing was done after my 3rd m/c, and no cause was found.

Could my uterine lining not be "thick" again yet?  How would I know??  Are there medications that could help me?  
I haven't called my doctor (yet), because I won't be able to afford any treatments/testing not covered by insurance.

I have researched Asherman's syndrome, but I don't think that's it becuase my period has been normal since 4 wks after the miscarraige (miscarriage).  

Any ideas??

[seattlemom2plus]

How are your progesterone levels?  Are those normal?  Did you find out any more information?  Give us an update when you can.

[BabyG2011]

Get an ultrasound. Some fertility clinics give discounted rates to those who don't have insurance to cover treatment. I think it's pretty reasonable. I had an ultrasound done a few weeks ago after a natural m/c to check if everything passed and how thick the lining was. It only cost $100.
A free method is to simply monitor AF when she comes around. For me on my heavier days I can actually see the lining in the toilet after I go pee. This won't tell you much about scarring but you can monitor the thickness of the shedded lining.
An ultrasound is a better bet to see if you have scarring. I actually had a laproscopy (belly button surgery) and that is when they discovered scarring near my Fallopian tubes. This surgery was paid by insurance.
You should start with bloodwork to check your progesterone levels as seattlemom suggested. This is the least expensive route. I think I pay about $26 for both hcg and progesterone blood test through the fertility clinic. Regular doctors charge my insurance much more. What scares me is what if my insurance doesn't cover. Then I'm just stuck with an inflated charge. So if it's related to fertility I just pay out of pocket. Of course I call my insurance company before any costly procedures and work with the billing dept to ensure they use the right billing codes. Clerical errors can be costly. They were not going to pay for my laproscopy but once they found the scarring was endometriosis they paid up. I kept telling them that's what I had but no one believes you when you self diagnose. I lived with it for years and they didn't look for it until I had trouble conceiving. I had to tell them just do the procedure and I would pay but with what they found there was no denying it needed to be covered by insurance. Jeeze...

[seattlemom2plus]

Great input BabyG2011 I think this information is very helpful for anyone under the circumstance.