Clearblue Digital accurate or not?

Nicola • I`m a 28 year old teacher from the UK. Had my rainbow baby in September 2017 after miscarrying twice.
I did a Clearblue Digital test on Sunday and it said 1-2 weeks which would make me 3-4 weeks pregnant. I've done another one this morning and it still said 1-2 weeks.
I'm worried because judging when I ovulated and last had sex I should be about 5 weeks which would show up as 2-3 or 3+. I had a miscarriage in March and really hope that it hasn't stopped growing 😔 I was just wondering if the digital test had the weeks wrong for anyone?