Another thought about your neck and armpits is that the doctors might have been checking out your lymph nodes - swollen lymph nodes can be a sign of infection, as well as other things. It sounds as though they suspect that you may have something other than diabetes. Sadly, being diabetic doesn't make you immune to other diseases!
Whatever the problem might be, no one going to be able to diagnose it remotely - there isn't enough information. What you need to do is ask the doctors detailed questions. Take a notebook along - write the questions down, and write down their answers. If they use any words you don't understand then ask them to spell them out - then you can look them up on the Internet, or post them here, I am sure someone will be able to help interpret them. I suggest that you ask the following questions:
- What sort of diabetes do you have?
- Have you had a C-Peptide test - if so, what is the level?
- Have you had a GAD antibody test - if so, was it positive or negative?
- Do they suspect anything other than diabetes - if so what?
Lastly, ask for a copy of the results of your blood tests. These will be lots of figures, and might not mean much to you, but it could still be a useful thing to have. Again, there are people here who will almost certainly be able to help you interpret them.
I am sorry that you are going through this rough time. The light at the end of the tunnel is that once you do get your blood glucose under control, then the symptoms of diabetes abate very quickly. If you do need to go on insulin, then that will get things under control extremely fast - although most people are apprehensive about this before it happens, most people describe it as a relief after the event.