Well, here is some advice from the NHS...
www.nhs.uk/conditions/stomach-ache-abdominal-pain/pages/introduction.aspx
"Stomach ache and abdominal pain"
"A stomach ache is a term often used to refer to cramps or a dull ache in the tummy (abdomen). It's usually short-lived and is often not serious.
Severe abdominal pain is a greater cause for concern. If it starts suddenly and unexpectedly, it should be regarded as a medical emergency, especially if the pain is concentrated in a particular area.
Call your GP as soon as possible or go to your nearest hospital accident and emergency (A&E) department if this is the case.
If you feel pain in the area around your ribs, read about chest pain for information and advice."
And...
I did not see how long the OP was out for when she fainted.
www.nhs.uk/conditions/Fainting/Pages/Introduction.aspx
"What to do if you or someone else faints
If you feel you're about to faint, lie down, preferably in a position where your head is low and your legs are raised. This will encourage blood flow to your brain.
If it's not possible to lie down, sit with your head between your knees. If you think someone is about to faint, you should help them lie down or sit with their head between their knees.
If a person faints and doesn't regain consciousness within one or two minutes, put them into the recovery position.
You should then dial 999, ask for an ambulance and stay with the person until medical help arrives. "
NotAnotherUserName1234 please do not put people off going to A and E because they post things on Mumsnet. You don't need to encourage them to go, but please just do not dissuade people or make them feel guilty for using the services which are there for them.