I was losing steady up until a few weeks ago, now I'm up and down week to week. So my 'gain' doesn't always stick lol. My docs have not been worried about the loss as baby is growing well and pregnancy has been progressing nicely.
I have also spent a good chunk of this pregnancy feeling sick but as long as I am careful about what I eat I've always kept food down (most of my vomiting was very early mornings before breakfast).
Baby is going to take from you what it needs first and foremost. As long as you are eating a healthy diet, and baby is growing appropriately, if your MD is not worried, you shouldn't be either, and just be grateful that you will be less than your pre-pregnancy weight when this is all said and done! I also know that this is not as big of an issue with those who are overweight to begin with... If you are underweight or normal weight to begin with there might be some concern that baby may not be getting enough nutrition. Those who are overweight have extra fat and energy to "give" to baby. I am not sure what category you fall in.
I think that you should must follow these tips to get effective results...
1. Drink more water.
2. Take low fat and carbs in your diet.
3. Avoid eating junk food.
4. Take a cup of green tea.
5. Must do some exercise like cycling or swimming.