Pregnant, dizzyness, vomitting, cold sweats, breathing difficulty, eating regular diet, told it was low blood sugar. Suggestions?

I am 15 weeks pregnant. Ever since I became pregnant I have had horrible dizzy spells I can t eat anything because it either doesn t seem appealing or I can t keep it down. If I am not laying down and get up for ANYTHINGGGG even for a second. I am blacking out/passing out, vomiting , shaking, having trouble breathing , cold sweats. And then I immediatly am backkk at the bed. I tried to leave the house for the first time in a month and I had all these symptoms just standing for 2 minutes in a line, and had to immediately turn home. I have been eating correctly and drinking lotssss of water and hydrating myself. I have been to the er about this many of times and its just getting worse. I have been diagnosed with low blood pressure the first time I went, which my doctor says is ok now. But now they are saying I have low blood sugar problems. Whateverrrr it is I would like to know. Because I am just miserable! :*(