Folic Acid & Pregnancy

For the past 4 years I have been trying to get pregnant. I have been on fertility drugs and nothing has worked. When I would take my fertility drugs, Clomed, I would get sick at the thought of taking them, it's as though my body was rejecting the drug yet I couldn't verbalize it. After gaining 15 pounds and feeling sick I stopped taking the drugs and decided to go back to trying naturally. It took my body 9 months to finally release the hormones from my body and begin to drop the weight. In addition I got regular yeast infections because of it and felt horrible. It's so funny how different things work for some and not for others. My sister in law has also had problems getting pregnant and was on the same fertility drug. Each time she got pregnant in the 2nd or 3rd month. Ive heard that when you stop worrying about it you get pregnant, Ive tried that too but somewhere in my subconscious it's always there. I read an article on folic acid, that it's supposed to help women who are trying to get pregnant. I see a nature path Dr. and she has me on all kinds of herbs and vitamins that are good for my body in general, but nothing specific for pregnancy. I have 3 boys so I shouldn't complain, I had hoped for a girl and have felt like my family isn't complete. I guess I never thought I would be one of the ones who couldn't get pregnant and didn't know why. I wish the Dr. knew why and could pin point the issue, instead it's a big question mark. I wish there was a machine that could zap you and tell the why's and how's of this health mystery in my life. For now I continue to read and search for other ideas,ways to increase my chances while my biological clock ticks and ticks...