It sounds like you may need to split your doses. Maybe you should talk to your endo about doing that.
You see, three hours after you take the meds, they'd hit your system all at the same time, making your BG drop. But because they aren't lasting the whole time, your BG goes up. Splitting the dose would mean covering those hours during which the meds don't seem to work as well (because they're wearing off, I guess) and keeping the lows at bay.
On the other hand, you said your BG goes up starting at around 5. Does it go up on its own, without eating? That sounds...interesting for Type 2.