Hello, 

I have also had a lump on the side of my neck since November (when I noticed it). I was told by my doctor to wait a couple of weeks to see if it went, it didn't so she referred me for an ultrasound. They measured it as just under a cm, it moves, little bit hard, I had the ultrasound last Monday and I am still waiting for the results to come back. I suffer with health anxiety too it's very debilitating! The best thing you can do is speak to your GP and ask to be referred for an ultrasound to put your mind at ease. If you have no other symptoms chances are it's fine. I have been losing weight since September, a stone in total, despite still eating well, so I'm hoping this is just down to my anxiety and nothing more serious, especially as I have had 2 lots of blood tests done, one in November and one last week and both came back normal. Hope this helps a little bit xx