Went to bed at 6.2 and woke up at 7.3, In the meantime I had a roller coaster overnight as I went up and down like a crazy thing with no bolus on board, yet dropped to 3.2 at 2am, fed carbs to come up, hit 11 shortly after and then came back down to 7.3 on waking, where I continued to drop.
The only thing I can think of was that yesterday I had to take the dogs out for a few short walks, but under normal circumstances, this wouldn't generate the roller coaster. I'll be keeping an eye on it tonight...