An overdraft occurs when money is withdrawn from a bank account and the available balance goes below zero. In this situation the account is said to be "overdrawn". If there is a prior agreement with the account provider for an overdraft, and the amount overdrawn is within the authorized overdraft limit, then interest is normally charged at the agreed rate.
It depends on the bank's policies on overdrafts. Most banks add interest on the overdrawn amount which will not be much considering the amount you stated.
There is likely to be an overdraft service fee changed, perhaps around £30 you may avoid it by getting into the black quickly (I'm just guessing about those possibilities)
Borrow £5 from your parents and bank it. . This will attract interest and affect your credit rating.
UK
Yeah more than likely