Weight loss during first trimester

Hello ladies! So I know that it is common to lose weight during your first trimester due to morning sickness. Well I have lost 20lbs in the last month and I having been taking medication for my morning sickness because it was so bad. I figured I would have gained a couple pounds back since being on it but I've actually lost more weight. Is that normal or is it something I should be concerned about? I have my first appointment Wednesday and I plan on talking to my doctor about it then, but I just wanted some other opinions. Also, I don't know if this makes a difference but I'm currently 10 weeks and 3 days. Thanks!