I often felt lightheaded in the shower. I thought it was the combo of warm water, standing for a period of time, bending up/down and meds. Have that shower chair handy for the next month. Eating wasn't normal for me or many others for a while also. My appetite wasn't there and I craved weird combinations of food.
I had to learn how to ask and accept help from family and friends. It's difficult, but necessary. It's also good to understand what it feels like to be on the receiving end of help. I think it made me more sympathetic, understanding and patient when others are recovering. I never understood why my friends were so tired after a surgery. I mean weren't they just laying in bed in the hospital? Why couldn't they read while recuperating? I totally get it now. You can't hurry the healing. Our bodies need time, rest, sleep to heal.
This recovery is a roller coaster ride, up and down. As far as night pain, be sure you're not skipping pain meds at night. If you were too active during the day your knee may be telling you to settle down. I hope you were able to get some rest.