Lots of people drink alcohol socially, but remember that any amount of alcohol can have an effect on both your health and ability to handle situations. The way alcohol affects you may depend on your age, body or even mood. It is legal to buy alcohol once you are 18 but when drinking it, make sure you are looking out for yourself and your friends.
It may also be that the amount of alcohol you drink makes you vulnerable because people often make unwise decisions when they have been drinking. If you think that you may have a drinking problem, there is lots of support available to people with the same problem as you, including groups like AA, helplines, and counselling.
If you are using illegal drugs, or misusing legal drugs (e.g overdosing or taking prescription drugs that are not yours), then you could be seriously damaging your health. There is lots of information online about what drugs are and which drugs do what, along with information on the health risks. There is support for drug addiction and misuse available to you, find out more online, call a helpline, or speak to your GP.