Hi Lucie
Its possible that your bg levels started to lower much earlier in the early hours to morning so you should start to get up in the night unfortunately and do some bg testing to find out what times the bg starts to change and then if necessary, alter the basal rates.
Not sure how the Vibe works but on the Combo, a bg of 3.8mmol would not allow any insulin to be delivered until some glucose or carb had been eaten first and then by doing another bg test which should read higher, the combo will then calculate insulin accordingly. Its difficult to know whether your liver came to yr rescue over the low bg but if you have been D for about 15yrs or more, then its possible that your pancreas will no longer release glucagon as a natural means to make yr bg levels rise up and the only glucose from the liver will be from what you eat or drink. Might be better maybe if you treat the low bg first with 2 or 3 jellybabies and then wait for about 20mins to see if bg goes up a bit and then do bolus for breakfast.
What has made yr bg levels go up really high....... its hard to know..... it could be that yr calculations over the amount of insulin you needed werent correct for the food allowing for the low bg or could be that weirdly, you might need to alter yr basal rates upwards from breakfast and then that should stop the huge rise or alter the carb ratio. Its not unknown for pumpers to just experience changes in bg levels with virtually no warning. Often worry comes over the infusion set wondering if its blocking, has the line got bubbles in it etc but often its just the body changing its need for insulin and confusiing peeps when it decides to start changing.
See what happens tomorrow with yr bg levels and then youll get to know whether you need to change the settings or not.