Not troll hunting. But. (Excuse my conception geekery). Something doesn't add up here, and I think you need to question what you've been told.
A woman or girl can only become pregnant from sex which occurs in the 5-6 days before or one day after ovulation. Implantation occurs 6-12 days after ovulation.
Therefore 7 days after sex, a fertilised egg most likely wouldn't have even implanted, meaning that the woman is not even technically pregnant yet. If under a slight chance (sex would have had to happen right on or immediately after ovulation, plus a short implantation period) it had implanted, it would have only just happened, ie, that day or the day before. HCG begins rising/doubling after implantation, and the levels are low enough normally that it takes a few days before the doubling is even noticeably different to normal, nonpregnant HCG levels. You couldn't pick it up on a urine test. You might pick it up on a blood test, but there isn't a sexual health clinic in the land which has access to a lab which can process blood results immediately.
Morning sickness isn't a given and doesn't start until HCG levels reach a much higher threshold than would be possible just following implantation.
There is no morning after pill which works 7 days after sex. Since the UK procedure for emergency contraception involves questions about when sex occurred, it simply wouldn't have been offered at this time. Even insertion of an IUD doesn't prevent pregnancy 7 days later.
As others have pointed out, the morning after pill prevents pregnancy by delaying ovulation. There's no foetus (blastocyst, at that stage, but whatever) to be removed.
Even if a pregnancy ends at this stage, you wouldn't be aware of it. The blastocyst would be too small to see with the naked eye. It's literally a few cells. Most women pass clots occasionally which would be much bigger than any suspected miscarriage at this point.
As the potential pregnancy was so early on an abortion would not be possible.
However one point - if services suspect sexual abuse of a minor then unfortunately it's perfectly correct that they don't immediately inform parents. Because unfortunately statistically, it's likely that the parents are the ones perpetuating the abuse. It's right that there are protocols to rule this out before you're informed. This isn't anything to do with actual suspicion of you, but the sad fact that some parents do abuse their children.