Hi sd!
I probably won't be much help on the technical advice side of things having only recently been diagnosed in January myself, but I just wanted to encourage you.
I had a similar experience to you. I am 39 and was with my daughter in South Africa where she was starting boarding school, I hadn't been feeling well, but put it down to the very stressful situation I was in. I did start to be worried about how quickly the weight was falling off me and I knew something was not right. I picked up a sinus infection on the plane over and went to the doctor who diagnosed T2 (because of my age) put me on metformin (1 per day). Boy, do I so totally understand your feeling - what the heck can I eat now - so landed up eating very little out of fear. Anyway, to cut a long story short, 2 days later I was rushed to hospital semi-conscious with acute diabetic ketoacidosis and my diagnosis was changed to type 1. I was then told about type 1.5 by a diabetologist I saw, who said, I could be type 1.5, but that speed of onset was unusual. I'm not telling you this to scare you, and as I said, I am new to this so don't even know if my experience was unusual or not, but just keep a very careful watch of yourself and how you are feeling - I was fortunate as I was staying with my mum and sister who are both nurses, but to answer your question, yes, you must take the diagnosis seriously.
One valuable bit of advice I followed, was to take the time to read, read, read about it, and, I am not sure if this bit is applicable while on metformin but, the more diligent you are in the beginning about keeping food diaries, and insulin doses, the easier it becomes down the line and the more flexible you can be. The GOOD news (even though it may not feel like it for you right now) is that it DOES get easier, it IS manageable. It is a total pain in the behind and an inconvenience but you only need to look around at this forum and see how much support there is out there. I also took inspiration from Sir Steve Redgrave who was only diagnosed the 3 years before winning his 5th gold - I liked his outlook in that he said he decided very early on after diagnosis, that the diabetes was going to have to live with him not him live with diabetes.
Good luck, and take care!