extreme nausea and weight loss

i am 10 wks pregnant and ever since i was 4 wks pregnant ive had severe nausea well i went to the doctors at 5 weeks pregnant saw i was 195. mind you pre pregnancy weight was 180lbs. i started to weigh myself every week by 7 wks i was 200lbs, went to docs at 9 wks i was back down to 180lbs. i know this isnt much of a concern but i weighed myself today and im 170lbs. I am eating 5 small meals a day but am so nauseous that i actually puke at least 2 times a day. and yes doctors gave me meds but still not helping keep food down just helping not feel nauseous all day long. i have tried ginger ale, 7up, crackers and carb like foods everything disagrees with my stomach. i have also found myself getting dehydrated fast and constantly drinking water which doesnt help my stomach. Baby is growing just fine but i am worried about if this keeps up like this. Any suggestions ?