Diabetes before pregnant

I am 25 and only weigh 108 but I was diagnosed with pre diabetes, my blood sugar was always really high no matter what I did to control it. Now that I'm 5 months pregnant all of a sudden my blood sugar gets so low that I almost pass out. It stays around 65 and goes lower then that. No matter what I eat it won't raise over 75. I've tried telling my doctor that and only response I keep getting is drink more water. I feel like if I drink more water I will turn into a fish. Is there any reason why my blood sugar won't raise no matter what I eat or drink?