Left neck lump 30 year old female

Hi everyone I'm 30 years old, Friday I went to the doctors about a neck lump. I had this back last summer ( July I am sure ) doctor said October then July so unsure myself now. How ever it was a pea size lump, in my left neck. I wasn't sure what it was as I did lose nearly 3 stone last summer as I expierence a hard time, I guess you can say a breakdown. Lost the plot a little bit and lost loads of weight in the process- so I guessed it may have always been there and could feel it now I was slimmer. Doctor wasn't concerned, said to contact if change in size. So the last couple of weeks I noticed it had in fact gotten  bigger, so spoke to gp Thursday who had me in on the Friday and checked me and said it had gone from pea size to grape size and said to send me for a urgent scan. Then a few hours later he had text me to say he spoke to the head doctor who had recommened actually aswell as the urgent scan to send me to head and neck specialist doctor within 2 weeks. Monday I had a phone call about an appointment for the head and neck specialist ( scared me even more how Friday I was refered and a few days later they were on the phone to book) yet haven't heard about the urgent scan. My appointment is Friday, I'm scared ***. Now I am thinking it's bigger again, thinking my shoulder looks swelled and keep thinking my left breast hurts to( how ever I am unsure if this is in my head ). Has anyone expierence similar ? Thank you in advance. S x