2.9 is a very scary number for your first hypo!
My first was a 4.1, much less horrifying.
To help with situations like this in the future, put hypo treatments EVERYWHERE. In your bag, your car, your jacket pockets, your bedroom, your kitchen (obviously lol), your bathroom, any room of the house you spend significant amounts of time in, in your desk at work, in the fridge at work....you get the idea, leave them all over the place so that if you are low you can spot some food/drink at a moment's notice and without having to think where it is or go wandering around looking for some.
Hyperglycaemia after getting low is definitely normal. With minor lows (around 4) it's easier to avoid since you don't have to eat so much so quickly, but with very bad hypos (<3) you don't want to be taking any chances, so the best course of action is to overcorrect slightly. It doesn't matter if you get high, you can always fix it later. But if you get too low, you may not be able to fix it....So when in doubt, always have a couple more grams of carbs. 9.8 is also a pretty mild high - many people on insulin find that their numbers get on a sort of rollercoaster after they get low.
It's very unfortunate you had such a severe hypo as your very first. I think most people are lucky enough to have a few fairly mild ones soon after they're diagnosed, which help them learn how to treat correctly without being in too much danger as well as developing hypo awareness skills. As you are having issues with hypo awareness, try to check more frequently and run your numbers a little higher than you usually would.