Your instincts may be quite correct. A hormonal imbalance can be at the root of your Pre Menstrual Disphoric Disorder, and also the reason it took you to four years to conceive with your first child, and related to the miscarriage you experienced.
Inadequate progesterone levels can be the common thread to all three of these problems. For this reason, I would recommend investigating it now, rather than waiting until after you have your next child.
The first step in diagnosing would be to chart your cycles in a very precise way. By learning to observe your cervical mucus in a very specific way, and keeping records, you will have a revealing insight into your hormonal state.
The quality and duration of the mucus, length of the luteal phase, and characteristics of the menstrual flow will all assist a physician with a trained and experienced eye in interpreting, and identifying the probable cause of your problems. It will also permit the physician to time hormonal tests very precisely based on your specific cycle, which is the only way to get an accurate hormonal evaluation, and diagnosis.
Treatment can then also be timed to coincide correctly with your ovulation and luteal phase, which is the only way it can be effective.
This is the path to a solution to your physical and mood problems, as well as your fertility problems, and lowering your risk of miscarriage, and preterm labor (you do not mention if that was an issue, but can be related to these other things you mention).
To not waste time, I would consult an NFP Practitioner so that you can quickly and accurately begin to track the specific information you will need about your cycles, so that you can take the next step of taking those records to consult with a physician expert in interpreting. The NFP Practitioner will be an invaluable resource to you in guiding you through this process.
We have lists on our website of both the NFP Practitioners, and Medical Consultants in California, and on our links page you can explore resources outside of California.
Your instincts are serving you well!
Sheila St. Joh