Hi ssbu,

First thing I'd say is that you've already done really well in letting people know about your worries and getting an appointment with the GP/Ultrasound! That's definitely a really difficult first step to do for some.

And since the ultrasound has come back normal that's already a really encouraging sign (you shouldn't worry about it being an "urgent" referral, from my understanding of it, that's quite usual for anyone who has a lump that the GP can't explain!)

If you are still worried though, I'd definitely let your parents know and try and get another appointment at the GPs, and go through the process again, it's definitely better to be safe than sorry! (just to remind you, according to the NHS website, less than 4 in 100 lumps are cancerous.)

You won't be wasting anyone's time, it's the doctors' and nurses' jobs to make sure we are all healthy!

Hope this helps! 

I'm no expert, just someone who's gone through the same kind of worries that you have, so if anyone more suited to answering this question does write something better, please listen to them instead of me!!