@fendertele
I'd agree with
@Fenn's suggestion to use a Libre sensor to check what's going on in general, otherwise definitely finger prick at the time lows etc are happening or when you feel something's not right.
If you've been used to eating a high(er) carb diet your body will preferentially use carbs to convert to quick access fuel in the form of glucose for energy, and when you get hungry/low it's a signal to top up with more carbs. However, when you eat a very low carb/ketogenic type diet, you're balancing this carby shortfall by using dietary fat and/or stored body fat instead. The fat gets converted to an alternative long term fuel in the form of fatty acids/ketones requiring a more complex conversion process.
If your body's not been used to using this dual fuel option there's generally a short transition period while it (re)leans how to do this, which can result in a temporary mini fuel shortage crisis, often causing short term but unpleasant "keto/low carb flu" side effects. So I imagine you've maybe been going low and feeling off because you've run low on available glucose and not yet got used to switching over to the alternative fatty ketones when this happens. And thinking about it, the symptoms are probably very similar to false hypos as they both happen when you run short of available fuel.