Lost weight

So far I have lost 19.2lbs through out my pregnancy. I haven't changed really anything and I'm not working out. All I do different is I try and drink 2-3, if not more, cups of water a day. I'm 13 weeks as of today, I just wish I could see the weight loss or even my baby bump.. I still feel like I need to lose so much more to be healthy for this baby. Does anyone else feel the need to be a certain weight to have a healthy pregnancy and baby?