weight loss in pregnancy

I'm currently 21 weeks 4 days and my pre pregnancy weight was 63kg. I lost a large amount of weight during my first trimester and beginning of second due to [i think] my severe morning sickness. The issue is, I still weigh less than my pre pregnancy weight (59.6kg). Should I be worried? I'm really struggling to eat well as I am still quite nauseous! Has anyone else experienced this? I just want my appetite back!