Hi C. G,
My heart goes out to you! Know you are being a great mom and doing what you can. :)I do want to say that I don't think calling a Dr. is always as necessary as others do at times. I say this because many times, children simply need love and affection for a bit and then will drift off to sleep. I don't know if you are spiritial at all, but I pray with my daughter, and it calms her. :) I suggest that to many moms. :)
Really, my best advice is to check and see if both kids are teething. One is about the age to get 2 year molars, and the other could be just starting. I highly recommend the natural teething tablets. They are wonderful! Also, and I know this will be tough, but try to stay calm and not stressed when tired. Your children, both will pick up on that and draw back in reaction. By drawing back, I mean they ultimately will react to what we put out there.
I can only imagine how tired you are. Is there a way to catch up on some sleep, someone who could take one of the children for a couple of hours so you can rest? If not, drink lots of water, and exercise. Well, actually, do that anyway. :) It sounds silly, but it makes you less tired. Oh, and vitamin B12's are great too for energy. Fred Myer has a chewable one that we often take. What a huge blessing to have such beautiful girls!
As for people telling you that you would have your hands full, this is my thoughts... God only gives us what we can handle. You can do it, just breathe. :)
Will pray for strength and energy for you my friend. :)
Hugs and Blessings,
K.S.