Im not sure where you are but here we have a free health clinic we can go to for that sort of thing...if you have one you can go there instead of your regular doctor. Your symptoms can be a lot of things. Its scary being young and going through it but if you arent pregnant remember protection every time.
Hunny you are 15!! You should not be having unsafe sex. I will not encourage a teen pregnancy. For god sake if your going to act like an adult be responsible.
you need to take another test if you can get hold of one, when you do take it with your first wee in the morning as this will give more accurate results, you maywell have taken the first one too early, if you are, you will need to tell your mum and go and see a doctor as well as you will need extra care during the pregnancy as your still growing yourself, but first off start with another test and see how you go