J.P.
I too am sorry that you are having a difficult time getting pregnant. I wouldn't wish fertility issues on anyone who wants to have a child, no matter how many children they already have.
I had fertility issues and wound up seeing a specialist to get pregnant with both of my girls. Clomid worked for me in combination with an HCG trigger shot and intrauterine insemination (IUI). I'll tell you what I know, but you have a lot of good questions that could probably be best answered by your doctor. Usually they have literature to give you regarding the meds you are taking for fertility issues. Are you seeing your regular doctor/OB or an RE? I would highly recommend the Center for Reproductive Medicine (CRM)- they have top-notch fertility specialists in both Minneapolis and St. Paul. I saw Dr. Kuneck, and I know several people that have had success with other doctors there as well.
I don't know the specifics of some of the drugs you are to take but over my 4 year fertility journey I have seen people talk about all of them on message boards that are related to fertility. Mucinex helps increase your cervical mucus, which is often dried up as a side effect of Clomid. I think green tea extract is also thought to have positive effects on cervical mucus. Some people drink a lot of green tea while trying to conceive. I did, figured it couldn't hurt! I took progesterone after ovulation and the iui to help build and keep the lining of the uterus healthy and continued it throughout my first trimester. You can take progesterone orally, via injection, or vaginal suppositories.
A couple of questions/things for you to think about, since you didn't mention in your post. Did your doctor do a fertility workup to identify your ovulation issues, and do you know why your doctor prescribed Clomid vs. something else? Has your doctor done a "Clomid Challenge Test" to see how your body responds to it? If you are unsure, Google it -there is a lot of info out there. Clomid works for many people, but there are many others that don't respond well to it. It also will help your doctor find the right dosage for you. Have you had a HSG or other test to see if there are any blockages in your fallopian tubes or uterus? If you are taking ANY fertility drugs, you should be having bloodwork done throughout your cycle to monitor your hormone levels, usually starting by day 3. And while expensive, the ultrasounds are vital for many reasons: to check to see that your follicles are growing, to measure their size and rate of growth, to make sure your ovaries aren't hyperstimulated and producing too many of them, to name a few reasons.
I don't mean to sound harsh, but nobody should be taking fertility drugs if they aren't going to be monitored in some way while they are taking effect. From your post, it doesn't sound like you have been told very much about the drugs/supplements you are to take, and it doesn't seem like you are being monitored throughout your cycle.
It's a lot to think about and I'm sorry if I come off as preachy. Lastly, I agree with the other poster that recommended the book Taking Charge of Your Fertility. It's what helped me figure out that I have ovulation issues in the first place.
Best wishes to you.