Hi and welcome Timbo
The thing about panic attacks is that there isn't always an obvious reason for them, I had them badly for nearly 30 years with no obvious trigger..it just happened. There is usually background anxiety going on though and as SG said, fear of the fear can make life very difficult indeed.
Best thing for PA's is knowledge, arm yourself with the info you need and in your case, the realisation that although Diabetes can be classed as an illness in some, for the vast majority it is just a condition that we manage as best we can.
The worst case scenarios are certainly not a surety so please don't think they are. There is lots you can do to manage your diabetes successfully, don't panic about the meds (I HATE meds but have got over that hurdle at last!) and read how well people are doing here.
Take care.