Hi there
It seems that you've felt under a lot of pressure to be accepted by your cousin and her friends and, as a result, have ended up doing things that you're not really happy with, like drinking alcohol. Your cousin is bullying and threatening you with the video she took, leaving you feeling unsafe as you don't want your mum to see it. No one has the right to make you do something you don't want to do like paying you for sex, or paying you to have sex with other people. You might like to think about whether you want to continue your relationship with your cousin.
A big worry seems to be the threat of your cousin having the video and her demands for money. It’s important to realize that if you give her money the problem won't go away. It is also important to be very clear that what your cousin is doing is wrong. No-one has the right to threaten you in this way. It would be great to go back in time and change things that have happened but it's not possible. Lots of people have said and done things that they wish they hadn't but that is just part of being human. What we can do though is look ahead and find solutions to things that are bothering us. It might sound a bit scary to suggest but what about talking to your mum. You might be frightened of how your mum will react but once your mum knows your cousin should no longer have any power over you. If you think that having that conversation with your mum is too difficult you can talk to a ChildLine counsellor on 0800 111 or through 1-2-1 chat or email. They could help you work out what you're going to say.
You also seem to be worried that you periods are late, If you only gave someone a blow job it’s not possible to be pregnant from this, however you said you don’t remember what happened. Periods being late can be a sign of pregnancy but they can also be a sign of other problems that would need to be checked out by a doctor or a nurse. It is important to think of your health though particularly as you don't say whether or not a condom was used which would protect you from sexually transmitted infections. You could talk to ChildLine about these issues and they'll be able help you on where to go for practical help.
Take care,
Sam