Hi, im currently going through something similar, but I started with chest pain, nearly a year ago then a couple of weeks ago a hard lump appeared on my sternum then 2 swollen lymph nodes in my armpits then 5 in my groin over 4 days, i also have had weight loss of a stone within a few months and night sweats. Has your doctor recommended bloods mine did a full blood check including checking for any viral or bacterial infections and glandular fever, as that can cause them to appear. Once all that came back clear i was referred on to hematology under the 2 week pathway. Currently waiting to se a spealist, its good that they have you booked in for a scan,  if you haven't heard anything contact your hospital that will be doing it and ask about an appointment date and ask to be put on the list if any cancellations happen they will call you and hopefully get you seen faster.  I understand how scary this is as a mum myself to two young girl instantly your mind goes into overdrive and its hard to not think all the scary thoughts , a nurse I spoke with a week ago said to me keep pushing them, and dont feel like your bothering them, you need answers so keep on it. If your gp hasn't done bloods call them back and explain its still there you would like it looked at again and bloods to rule out and infection xx