IMHO, you should always seek medical advice if you feel that ill.
If it helps, what you describe isn't something I've experienced. I haven't been diagnosed T2 for very long and I've been on Metformin and testing for 3 weeks. In that time, my highest glucose reading was 14 and the lowest 4.2. I can't say I've felt that unwell (although I've sometimes not been on top of the world, either).
I do know that what I eat hugely influences my glucose levels, with exercise being another factor to be taken into account. Someone on here said when she felt the signs of high levels coming on, she got her walking shoes on and went for a brisk stroll. I took that to heart and I've found that it works for me.
I've gone onto much lower carbs, cut out sugar and everything sweet completely, and eaten less but more often through the day. On those days when my levels are low and reasonably stable I've felt very much better in myself. The trick, I think, is to learn how to do that more often. I'm hoping that some long overdue weight loss might help.