The lasagna could definitely account for the 178 during the night, Larry. Lasagna is both very high carb and very high fat. What that means is that it will raise your blood sugar very high but sometimes the spike will be quite a bit later due to the fat content. It is also quite possible you were a lot higher than 178 earlier in the night. You might want to do some testing of blood sugars 2 hours after eating to see how different foods affect your blood sugars, and in the case of something like lasagna or pizza test 3-4 hours later as well. Most of us find we can't eat those foods without getting a large spike.
As for the sweating during the night, it sounds like a dumb question, but are you sure the room wasn't too warm? I was getting nightly sweats and my blood sugar was fine. When I stopped using my down comforter and went to a lighter quilt they stopped...duh!
It's hard to know if you'd been low during the night, you can wake up with dried sweat that happened earlier and when you test you are not low, your liver can kick in and raise your blood sugar for you. Sometimes you can go very high and then your liver kicks in and you rebound too low. It would be hard to know for sure without knowing how long after eating you tested.
Yes, it is a good idea to test before bed to make sure you are in a healthy range to sleep (say 80-140). Lows are less common when you are not on insulin, but they can happen. But my main recommendation to you is to test after meals so you know the effect carbs have on your blood sugar. As others have said, it is not just sweets you need to be concerned with, but carbs.