I changed pills and my bleeding was shorter and less voluminous?

Hello, I had been taking the Marvelon contraceptive pill for several years and it was no longer effective (bleeding between periods). I made an appointment with my doctor who prescribed me a new contraception (tricyclen). I waited for my period to start (first day on Tuesday) and I started my new medication the next day (Wednesday). Usually, my periods are abundant and last at least 5-6 days and sometimes more. However, this time they lasted only 3 days (Tuesday to Thursday) and this is not normal for me. At that time, I had only taken 3 tablets of my new contraception (on Wednesday, Thursday and Friday). Usually with marvelon, I took the pill from Friday to Thursday.