I had some trouble getting pregnant after a miscarriage and we found out that it was because I was not ovulating normally. It had taken about 9 months or so to get pregnant the first time and then after the miscarriage, my cycles never got back on track. The doctor was able to give me some medication to jump start my cycle and force a period, then gave me a very low dose of Cholmid to help with the ovulation. Using ultrasound, they were able to tell when I was going to ovulate and told us to get busy during that time! It worked the first month (although it had been 5 months since my miscarriage) and it was very non-invasive (all of the medication was in pill form and I just had to take certain pills on certain days).
It sounds like your cycle might not be normal, but the only way you will know what's really going on is to see your OB. I would also agree with someone else's post that it may be your husband that needs to be checked also. If after seeing your OB, they don't have an explanation, I am sure they will suggest having him get checked out as well. I wish I had better advice. I know how frustrating it can be to wait so long to conceive, but just try not to stress about it and let the doctors see if there is a simple solution for you. Sometimes we just have to wait for God's timing! :-)
Good luck!