I feel like a slug

I remember how quickly I'd fall asleep once that fatigue hit me post op, and I was shocked, as normally I'm a night owl and stay up quite late. Immediately post op, I was still a night owl, but at about a week post op, I started getting super sleepy and nothing could keep me awake. I often fell asleep on the couch watching Netflix, lol

Don't worry; it will pass.

Yes EXACTLY! I felt like I had more energy in the previous few days post-op and then suddenly it was like BAM...fatigue-wall.

Yup; your body is demanding rest. You had major surgery, plus anaesthesia, and you just need time to heal. I think the brain fog/fatigue is our brain's way of forcing us to slow down to get the rest we need.

Don't fight it. You'll soon feel better again.