Feeling discouraged....

I have been to the doctors and ER twice now because of being dehydrated because I haven't been able to keep anything down including fluids. First time I had fluids it lasted two weeks until I was dehydrated again. I had fluids again on the day before Christmas eve and I am already throwing up everything. I am 12 weeks and had a ultrasound on Christmas eve. Baby is healthy, growing, and well. But I am getting so discouraged :( makes me wanna cry. Why am I having such bad morning sickness? Anyone else been through this. What did the doctors do for you? Any feedback or advice from women who been through this would be appreciated!