First Trimester Questions..

Hey ladies, today makes week 9 for me and I'm feeling fine. Thing is, even w me feeling okay, I haven't been all that hungry. I've lost 5 pounds already because I haven't been eating like that. Sometimes because I can't keep the food down, other times because I have taste for nothing but water. My question basically is what can I do to keep from losing all this weight because my doctor wants me to gain my weight back (it keeps dropping so I'll see what I weigh at my next appointment Friday). Any foods or tips to help me out with what to eat, even when I feel like I'm not hungry at all?