How far along am I?

[Lisa2008]

Bit confused. I have pcos and irregular periods. last period being March 3rd.
Negative test on april 19th ( I take tests every other week usually due to irregular periods.
Found out I'm pregnant 1st of May and so midwifes saying I'm 11weeks plus. Going from last period.
But if I had negative test on 19th April then surely I can't be 11 weeks plus.
Im just so worried I had a miscarriage last march and I can't have 1 day where I'm happy and looking forward to my pregnancy. I keep thinking about this doom day that's coming up ( my scan on 2nd June) breast are killing. Still being sick and generally not feeling good at all.
I will explains this to midwifes on Monday but has anyone else been in the same position? I'm fearful to go for my scan and only be a couple of weeks and then have to return. The waiting game is eating me up but I don't want to go in too early.. Nor too late if they are right on dates.
God I'm so confused.

Miscarriage in March was last year incase anyone confused

I'd suggest the very furthest along you could be was 8 weeks.

Negative test on 19th April so for arguments sake let's say the earliest it would be positive would be the next day, April 20th and that could have been 10DPO meaning you ovulated 10th April. Between 10th April and now is 6 weeks but normally you have 2 weeks between LMP and ovulation so you have to add 2 weeks. So 8 weeks at most.

If your test was only "just" positive on 1st May you can assume you're closer to 6.5/7 weeks pregnant.

Congratulations!!

O agree with above. Still, you need to go to your 12 week scan and mention your periods are irregular so you're not sure if it is 12 weeks. I had the same, scanned at "12" but I was only 7 so had that scan and then back at 12