Dizziness, nausea, weight gain with normal thyroid levels, please help?

I am 31yrs, relatively healthy until about 2 years ago when I had my twins. Shortly after delivering them by c-section, I've had dizziness that 1st starts with a sick/nauseous feeling in my upper stomach then turns to dizziness(feeling of fainting, not that the room is spinning), then have a feeling in my neck like a chocking feeling. I've gained weight in upper body with my face more round/fuller (even with excercising & bearly eating due to nausea). My docs have checked all checkables, thyroid, cbc, cmp,ANA, hormones, done CT of brain & neck I've being to endocrinologists, the only lab that was abnormal was the estrogen which was zero, actually not detectable. I feel like I am slowing dying & no one knows whats wrong with me. I can't stand this dizziness, nausea & weight gain thing. PLEASE HELP