Although you are at 4.8, your brain has not caught up with your body yet - this is why a lot of people over treat a hypo, because they don't feel like they've had enough food intake yet to correct their test result.
4.8 is still at the low end of acceptable, you should aim for about 6 after treating a hypo.
Also, the DVLA state that anyone with diabetes should not drive unless they have a level of 5.5 or higher, and that if you need to raise your level to this before driving, that you should have had it at least this high for a minimum of 45 minutes before getting behind the wheel of a car as otherwise your mental capacity can be impaired, which sounds like is what you are experiencing.
You seem to have a good idea of what to take to treat a hypo, but may I suggest that a slice of bread may be better than an apple, as it will sustain your higher sugar level for longer. (I tend to go for a slice of toast and jam if I'm at home, somehow the heat of the toast seems to help as I feel extremely cold if I have a hypo).