This clears that you have to eat more, yes, you will lose weight
during your first trimester
, thats normal , even my wife also had the same problem. but after 5 th month she started gaining weight and in her 9 th month she was 26 pounds more than her normal weight and we checked to your doctor about this weight gain, he told it is normal. Actually, a pregnant women should gain at least 12 kg more than her actual weight. So eat well, eat healthy and be happy.