Sorry to hear your going through this. If I was you I would check out the NICE guidance and assess yourself if you feel you meet the criteria for ultrasound and discuss this with the doctor. This is what I did. I've had my ultrasound and a FNA so waiting on results. It's such a worrying time and all the unknown feels a bit much. 
 

Was it a gp who referred you for ultrasound? Maybe ask for a different gp or referral to ENT? They are the specialists. My bloods came back normal too but my lump kept growing 

It was the gp who referred me. Can I ask how quickly did your lump keep growing? In the space of two weeks would you have had much growth? 
I'm trying to not panic but it's so hard when so many people have stories of normal blood results etc! 
Sorry could I ask what FNA is? I hope your results come back quickly for you and all is well! 
I may try and speak with another doctor because honestly I'm not sure I can handle waiting what could be months to have any more testing. 
 

Mine tripled in size over 6 weeks and then it's kind of stopped growing. Right now I'm at 10 weeks living with it and it's roughly the length of a satsuma and protrudes a little. 
 

Over 4 weeks I spoke to three gps and on the third time I went prepared knowing the pathway and how to discuss next steps. From there I was put onto the cancer pathway and with this you have to be seen by a specialist within 2 weeks. I think there's Information on this online and shows that it should take x amount days to be treated  etc. I'm a bit of a researcher I'm a nurse by background so can't help it. 
 

fna is fine needle aspiration