Hcg levels quadrupled within 7 days

I first got bloodwork at 5 weeks 3 days and my doctor wanted me to get more bloodwork so at 6 weeks 3 days I got more bloodwork. The next day I saw my doctor and she told me they quadrupled and my hcg levels are now at 22000 and something. Is that normal for 6 weeks 3 days. This is my second pregnancy and I never calculated my hcg levels before lol