I am so sorry to hear that you are in such pain!! I get migraines too and it's tough with kids. Is there any medicine the doctor can give you? Well this is what I do when I feel one coming on:
Darken the room, quiet, put temp on the slightly warmer side, wrap up in bed to feel warm and comfy.
Keep my hands and feet warm (learned that through biofeedback) to keep bloodflow going to extremities. This has helped me a lot!
Caffeine (I know you cannot have too much).
Ice pack to the neck.
Try to relax as much as you can (my migraines start with tension headaches).
And I get the kids as far away as possible. My husband is very helpful with this. What about friends and family? If I can just get an hour or 2 to myself I can usually pull out before the migraine gets too bad.
But at this point with you on day 3 - that is tough. I know there are injections you can get during a full blown migraine that are said to help but I've never had one.
If your regular doctor doesn't know much about migraines, try another one. Seriously. Ask you OB/Gyn for advice on what you can safely take. Consider learning biofeedback if your insurance covers it. There is probably a lot of free online info too.
I really feel for you. Migraines are so debilitating and the pain is something unline anything else. Being a mom makes it so much harder to take care of yourself and migraines make it even harder to take care of the kids. Personally, to me, this is an emergency. 3 days in excruciating pain and kids to care for and being pregnant requires immediate action. Get your hubby on the phone to friends and family and have someone else take care of the kids until the migraine is GONE. Toughing it out is not helpful for you, your children or your fetus. Go to the emergency room if you have to. I hope you get some good advice from moms who know how to handle migraines while pregnant. And I really really hope you feel better soon!