I've lost 20 pounds sense I got pregnent.?

That's fine I lost around 28 pounds u will eventually gain either all or some back.

I didn't start putting back a lot of weight till I was about 22 weeks pregnant

I sure don't look like I lost weight

I lost about that also. I am 33 weeks now and haven't put any back on but did stop losing after morning sickness was over.

I lost about 11 with my daughter, it's pretty common in the first trimester usually caused by food aversion and morning sickness. your Dr will say something if he/she is worried about it.