I think the best thing would be to make sure that you are definately pregnant before you start getting worried and blowing things out of praportion x You can buy an over the counter test or if there is another doctor at your mum's surgery im possotive that if you have a private word they would be more than happy to dicreetely do the test for you with strict confidentiality !
If you are pregnant you will have to talk to your mum and the earlier the better. She may be a little disapointed but she loves you and cares about you and will want to help you no matter what, its the way a mother is =)
Then you need to decide what you want to do which is easier said than done i understand. Since you have ruled out abortion you can look into adoption or keeping the baby. You need to look into the best interest of you and you alone! Dont feel pressuised into doing something that you are not happy with! Having a baby at such a young age may not be practical but it all depends on how you feel deep down. If you love the baby but cannot keep it because it would not be best for them or you then you must know that if you found a great and lovng family that he or should could have the chance at a happy and normal lifestyle. It will be a tough decision for you but you have friends and family to support you. you are lucky that you have a caring boyfriend who is matture enought to help you through this but make sure that you are not doing anything simply to please him or to make sure he stays with you, whatever you choose to do must be for you and no one else x
Goodluck in your descision making process and dont worry things will be alright x let me know how you get on best wishes claire