The more hypos you have in a row, the more likely you are to find your symptoms go away. If you can run without hypos at all for a bit (this may mean running your bg higher than normal for a while) you will probably be able to get your warnings back.
This is the 'official' answer you'll usually get, HOWEVER... I would also say, what made you check your bg those times when it's gone down to 3.2? Was it part of your normal testing regime, or was there something going on that made you think, maybe I'll just make sure? Because those weird intuition things are not to be dismissed, in my opinion. I still consider myself to have hypo warning symptoms even though I've long since stopped having the ones they put in the textbooks. I have had to retrain myself to spot them and be very attune to what's going on.
so in summary:
-pay close attention to the things that are triggering you to check your bg, and try to learn from them
-run a bit higher than normal to avoid hypos for maybe 3 to 4 months
- oh, and always check before driving, whatever else you decide to do.