I know this is a long way off as levels at 15.3 at the moment, however if levels drop below 4 do you still have your insulin? Just trying to get a grip on everything.
If you drop below 4 it's best to treat it as a hypo and treat it with glucose or something sweet. You shouldn't miss your insulin (unless your nurse has told you something different) but, depending on the situation, you may need to adjust the timing.
Hard to answer in detail without an actual scenario.