I have had so many migraines for so many different reasons, that I hope I can help you. I find for myself migraines can be caused by a lack of certain vitamins, as well as foods that your digestion doesn't agree with (mine is dairy). You may have developed some food allergies as well, when you were pregnant with your son that you weren't aware of. I noticed myself the first time I got pregnant, my digestion was AWFUL and the doctors weren't smart enough to tell me to eat digestive enzymes for the acid reflux problem I was having while pregnant.
Also, work with a great naturopath. They can help you so much. MD's really don't know very much about cause and effect. It's more about drugs to mask symptoms.
Here are MY recommendations:
1) Make sure you have enough Magnesium in your diet - lack of this can cause migraines.
2) Make sure you are eating enough healthy foods - fruits, veggies, meats, potatoes, etc, so that when baby is feeding, he/she is not robbing you of vitamins YOU need to function.
3) Eat more often, and eat more than you did when you were pregnant. Include with that - drink LOTS of fluids. Make yourself smoothies. They're great - full of nutrition if you use fresh or frozen fruit. Lack of fluids have also cause me to have migraines.
4) Avoid Processed foods that are low in nutrition and high in salt and calories, and don't help you with the higher amount of vitamins you will need for yourself.
5) Make sure you are eating a lot of uncooked foods (pineapple, apples, salads) so that you have all the digestive enzymes you need to digest properly.
6) Take a GOOD live-food nutritional supplement - but make sure it isn't overloaded with vitamin A. Also, make sure it has lots of B6 and B12 in it. I'm convinced that the RDA amounts for these vitamins are much lower than what we really need.
7) Take a good probiotic (good bacteria).
Whatever nutrition we AREN'T getting, babies steal from our bodies. After my first child, I realized I didn't have enough calcium in my diet and I ended up with 7 cavities. The other two I had, I was clued in, so I had zero because I took a great calcium supplement. Same principle applies to your migraines.
For me, acupuncture for migraines didn't work, but other people say it's worked for them.