Hi,

I'm trying to understand the dates that you've given us... Cycle day (CD)1 was boxing day, and you had unprotected sex on CD3, right, when your period was almost over. That would make you CD 14 today (Monday), is that right? And the nausea and vomiting started on CD 8?

How many days is your usual cycle? Most of us ovulate around 12-14 days before our next period starts, and sperm can live up to 5 days inside you. So IF you have a really short cycle of 20 days and a short luteal phase of 12 days, you MIGHT have had a sperm from CD 3 meet your egg when you ovulated on CD8. BUT it's generally accepted that pregnancy symptoms don't start until after implantation - even if it fertilises, you're not pregnant unless the egg implants, and that generally happens 6-10 days after ovulation. So in the unlikely scenario I've described, implantation could be today at the earliest, which means any symptoms you've been having for the last 5 days are not going to be related to pregnancy from sex on CD3.

Having said that, are your bleeds always so short? Some women fall pregnant and have a light bleed which they mistake for a period.

You are right, though, saying that morning sickness can start before a positive test, though not before implantation.

It sounds to me most like some nasty, unpleasant tummy bug, for which you should see your GP again soon, if it doesn't respond to the medicine he's given you already. If you see him again ask him for a blood test to check for pregnancy, just in case, and make sure any medication he gives you is safe to take when pregnant, until you get blood test results back.

I hope that helps.