That’s a combination of carb depletion, and the water you’re now dumping because of it. It’ll pass. The biggest reason people dump so much weight at first is typically just water retention. Most don’t realize how much they hold, with as much Insulin as you were taking, I’d imagine it’s a LOT!
While it’s NOT the answer to everything like many think it is, SALT! This is completely overblown most of the time, but in a case like yours… make sure you’re getting it in! Dumping water that fast will always equal an electrolyte imbalance. They all matter, but the biggie is Sodium. The majority of electrolyte drinks couldn’t replenish them if you drank a case of it, which is why so many make their own. LMNT is actually a good one, but a little pricey.
For a type 2 to not be able to keep things in check with 130u a day… you’re bad my friend! So I’d assume you’ve got a lot of water coming out, that and the carb depletion would have probably been worse than most. Good news is, it’ll self correct. You’re already at half, so that’s awesome.
Something to keep in mind, don’t do the butter chugging version of keto while on Insulin (or at all really) Insulin stores stuff, not just carbs. It stores fat too, it also drives nutrients into cells (which is good), it’s not all bad but you gotta keep that in mind. As timing will matter. Also, one of the bigger points is to get Insulin to near basal limits most of the time. Seems you’re good with the sliding scale since you dropped it by half already so you should be good, just keep adjusting whenever you can. It’s only the T1D’s that are stuck on it for good, you should be able to get off at some point, just may take a while.