Morning sickness stopped after one week

This is my first pregnancy hence I think I am more paranoid: I found out I was 6 weeks pregnant about 1.5 weeks ago and went to the doctor to confirm my pregnancy. We could already see the baby’s heartbeat through vaginal ultrasound. I had morning sickness for about a week and it was so bad. I couldn’t keep anything down and felt terrible the whole day. Then, the morning sickness is gone SUDDENLY. I feel like my normal self again for almost half the week. My appetite is back and I don’t feel so lethargic anymore. Now I am a bit worried. Is it normal to feel okay so soon? Now I am about 7 weeks pregnant.