Suspected Subungual melanoma

Good morning all

I am worried sick! I had what I thought was a bruise under my toenail and realised lately it has still not grown out after over three years. My nail are very sensitive, for example I cant have a nail varnish layer over it as it hurts and I can feel the sore most of the time in the background if that makes sense. More recently my whole toe is a bit achy too. So i saw my GP on Tuesday and he called a colleague in who looked at it too and she looked through a special magnifier thing. She said "there is not blood spatter there, so its not a bruise" and they both kept saying Subungual melanoma and i needed a 2 week urgent referral. He sent pics off to the hospital and now I have a appointment on Monday. I am so worries I have not slept well for days! What else could it be if not a melanoma and not a bruise? They seemed convinced it was not a fungal thing either. (I thought I would just get anti biotics for a fungal nail or something and leave!).....Any help or advice gratefully received. I know Monday is nearly here, but seems an age away! What else can it be? Thanks :)