If you ever overdose on meds all you need to do is drink lots of water to clean out your system and you should be just fine.
Pffft... I wouldn't count on that if I were you...
Yeah man, you wouldn't have got high from that. Basically, here's quite a simplified explaination of how drugs work; in your brain there are these things that make things happen called neurotransmitters. They pass along these things call neurons, and by doing so let your brain know how it's supposed to be regulating your body. This includes a plethora of administrative stuff, like, when you're supposed to be feeling pain, your emotions, when you should be awake and asleep, lots of stuff like that.
Now drugs effect the way your neurotransmitters work, and there are three basic types. Stimulants, deppressants, and halucinegenics. Stimulants increase the productivity of a particular neurotransmitter by allowing it to move across neurons easier. For example, caffine is a stimulant, and when you ingest it, you're increasing the productivity of neurotransmitters which allow you to feel awake, and to an extreme extent; hyper. Painkillers are a depressant, and, as you might have guessed, they inhibit neurotransmitters involved in the process of letting your brain know that you are in pain. They don't actually 'fix' any problems, all they do is mask them. And hallicinagenics stimulate various parts of your brain which are involved in processing information given to them by your sensorary organs, meaning that if you take them, you hallucinate.
So anyway, taking too many painkillers can't make you high. All they really do is prevent your brain from noticing that things are happening to your body. Oh, and be careful with that overdosing thing, some painkillers are much, much more volotile than others. Beware of any containing paracetamol, for example. One of my second cousins actually died from taking a standard dosage of painkillers whilst they were drinking. It sounds as though what you took wasn't as strong as what she had though.
(I've just realised I forgot to mention her death in the death list in that other thread, but I didn't ever know her that well so I guess it must just have slipped my mind at the time).