Honestly, I find this advice (the PB&J sandwich) to be a bit "old-school". It worked when we used insulins like NPH and the low came about because of it starting to peak, but for being really low, the peanut butter (and perhaps bread, especially if high fiber i.e. healthy) will actually SLOW the aborption of the sugars. I can see eating the sandwich after the BG is confirmed to be rising if you're concerned with too much IOB that will cause a subsequent crash, but to treat the low with it immediately isn't something I would advise.
Did you try glucose drinks? Any juice or sugary candy (Skittles, chewable) should do the job. OR you could do like a hungry bear, grab and eat everything and then suffer the consequences (Which I do some times! :/)
Capri Sun juice bags,the ones marked "25% less sugar",have 17 gms carbs each and work well for me. Tasty, Work quickly, different flavors,low in price.
Another vote here for Doug. Those little bottles of Dex4 really work fast. Expensive, but if you're crashing that fast that's the way to go. I don't like the "chalk" either!
IMO, Juice takes too long to work. I always end up over doing it because that feeling of imending doom does not resolve until the juice kicks in. Juice has to be processed by the liver and that takes forever. Use Glucose Tablets! They are the quickest resolution. Good to eat 3, then a small snack for staying power. The Glucose Tabs do NOT have to go throught the liver...go right into Blood stream.
I have found that whole milk does the trick for me. I was down to the mid 50's one time and my wife brought me a cup of milk with a teaspoon of sugar mixed into it. BAM! I could actually feel my sugar going back up.
Just because it works for me doesn't mean it will work for you though.
I find that juice takes too long and then I go into a high. I hate the taste of the glucose tabs. The glucose tabs are hard so you have to chew them which takes time when you are dealing with a low. It's also embarrassing trying to chew some candy if you are in a yoga or exercise class.
I use Honey Stingers. They are made from organic natural ingredients and are soft and chewy. They actually melt in your mouth which is much better than trying to chew a hard candy. Ten chews are 38 carbs which means each chew is 3.8 carbs. They work fast. I can take 1 to 4 chews to bring my BG up depending how low I am, without going too high. You can get these in sporting goods stores as they are used by runners. They are also cheaper than glucose tabs and taste better!
Honestly, as much as you hate glucose tabs, they do work the best (or glucose gel, as others have suggested), and might be worth it considering the alternate.
For me, I almost always go over 15 carbs, and I check in 10 minutes just to make sure my BG is rising. Not to see if it's back to normal, just to see if it's stopped its downward fall. Just keep track of how much you go over, and then bolus for it. Even if it means taking insulin to cover 20 carbs when your BG is 90 (if you treated with 40 carbs), that's fine.... it'll soften the resultant spike.
I take smarties. I like the taste of smarties better than glucose tablets and they are less bulky in a pocket. I also take kids juice boxes but smarties work quicker than juice for me though.