pregnancy and tricare

I had little difficulty with tricare when I was pregnant with our son, but this pregnancy has just begun and nothing is going well. I'm allergic to one type of medicine they prescribe for nausea, so I have to use the more expensive kind. I can't seem to get my meds refilled, which I was able to do before. I don't understand how narcotics are not only refilable and usually don't have a cap on how many you can take, but a medicine designed for pregnant women is policed as if it were made of solid gold. How do you fight something like this? What am I supposed to do when I get dehydration to the point that I can't take care of my son thee way I need to while my husband is gone? What is it going to take for tricare to realize that sometimes things can't work the way they think they should?