Mine must have started around 5 weeks, I never found out I was pregnant until I was over 7 weeks along. I was on holiday from week 5 to 7 and I honestly thought I was dying as I felt so incredibly sick all the time and could barely eat anything, I went to the GP when I came back from holiday to beg for help and then he told me I was pregnant!!! I'm not surprised that I have had bad sickness, I could have foreseen this as I've always been sensitive to hormone changes, like when I started or changed my pill, I would be sick for days.