Get this taken care of now and don't do what I did. My doctors would just prescribe different sleeping pills, anti-depressants, put me on a different birth control pill (even though my husband had a vasectomy). All this did was mess up my body even more, to the point of almost no return.
Your hormones, thyroid, and adrenal systems all work hand in hand. When one gets out of balance, the other two pick up steam and so on. Your hormones have gotten out of whack with the pregnancy - find a doctor, preferably a DO (dr of osteopathy) who will want to find and fix the problem rather than just mask /temporarily fix it. Get Dr. Christiane Northrup's book, Women's Bodies, Women's Wisdom. Have an in-depth hormone testing /blood to check ALL three Estrogen, Progesterone, Testosterone free /unbound levels (found my Progesteron and Testosterone were at zero - I also felt completely crazy just days before my period would start). A saliva test will check your neurotransmitters (found that my Serotonin was almost at zero - so much for sleeping pills). Thyroid is the energy section - my temperature was in the low to middle 97's. My feet were always cold too. Big signs of low thyroid. Check viral panels - see if you have any active viruses going on that is preventing your body from working correctly.
Your doctor should start working on one system at a time and hormones are usually a good place as this is the 'feel good' section - get you to feel better while you get started. If you are willing to drive out to Anaheim Hills, I love Dr. Mary Berry ###-###-####. She was the first doctor that took the time to work with me and figure things out, few and far in between from other doctors.
Are you exercising? This will also help. Get good and sweaty. I know it is very hard to make time for this with two little ones but you need to put yourself on the list, otherwise you won't be able to do all that you need to with them.
Suzanne Somers is another author to get into reading. She may have played dumb blonds but she has got to be one of the smartest people in the world of health. She does her homework and talks with doctors on the cutting edge. I started with her book, The Sexy Years, entertaining and informative.
Good luck and know that you are NOT alone in this.