I have been on LCF for about 18 months now. My BG averages between 4.2 to 5.8, with an occasional 6. When it started going below 4.8, I started to get some of the symptoms you describe, and I now that I need a boost. I carry Fruit Pastiles around with me, and use them.
These occasions are rare, I can count about three in the last six months, and I think that early warnings are if I start to feel a bit 'strange' meaning not my normal self. I will do a quick check to see whether BG might be the issue. Portable kit is handy to have around. I don't have high blood pressure or similar ailments which might cause such symptoms, so normally attribute them to low BG and respond accordingly.
I have had one episode in the period since diagnosis, which seriously worried me. Early this year, I was away for a weekend training, and traveled by road. When I arrived I felt quite 'strange' faint, sick and dizzy. I quickly checked my blood and found it down at 2.5. I was able to take some sweet drink and a snack and 1 hours later it was back over 4.5, and I felt better.
The worry of course was driving in that condition? Now, I am more careful and check BG before travel, ensure that I have eaten and have plenty of fluid available and an emergency pack of chocolate of similar just in case. Fortunately, it hasn't repeated itself and when I spoke to the DNS and GP, both said that it was probably because I hadn't eaten before travelling and not to worry too much about it.
For me, I hadn't felt the affects of low BG coming on, perhaps because I was driving, but that has made me much more alert to the problems of missing meals etc. And I ensure that I follow my routine of eating 3 regular meals a day no matter what else is going on.