Hello
It sounds like you have been through a really tough time. You are right it was illegal for him to have had sex with you because you are under the age of 16 - but it's really important that you know that you haven't done anything wrong. If you wanted to press charges against him this could still be possible because according to the law you aren't able to make that decision to agree to have a sexual relationship. I can see that can be a bit confusing and for more information about that you can check out the Brook website page 'Consenting to sexual relationships'.
I'm sorry that you aren't that close to your family, but it sounds like you do have good support from your sister. You did the right thing to talk to her about this; she gave you some good advice. Adults like this man you describe can be very forceful and try to get you to feel bad or scared about what happened. That's how they try to trap young people in relationships that are abusive. These kinds of people are very good at making you feel like you've done something wrong when, in fact, they are the ones taking advantage of the situation and doing their best to make sure that the young person they are hurting never tells so they don't get into trouble.
Your GP can give you a pregnancy test, but you can also get one done at a Brook clinic - you can check the Brook website and see where there is a clinic close to you. You could also visit a family planning clinic - you can find out where there is one close to you by visiting www.fpa.org.uk.
You've been really brave and there are other adults out there who can help. Do you think you might feel able to talk with your sister about the situation at school and how you are feeling about what has happened? It sounds like this has been really hard on you and it could be really helpful to have someone to turn to.
You are also always welcome to talk to a ChildLine counsellor, they are friendly and understand the sorts of problems you might be worried about. They won’t judge you or put you down and they are not easily shocked. Instead, they will listen and help talk you through your options.
If this man does still try to contact you, maybe you can consider telling a trusted adult about this. That could be your sister or a teacher in school for example - but you can also always contact the police about what he is doing and about what has happened. You haven't done anything wrong and there are trusted people out there who can help you.
Take care
Sam