2 workouts in a day - newbie qts

OK - maybe a stupid newbie question...

But - yesterday morning I had one of those extremely rare occurances where I was awake at 6am and coherant enough to be social and aware enough not to drop weights on toes and whatnot, so I got my ass out of bed and went to the workout room and did my upper body workout and light cardio before the rest of the house woke up and it was time to get ready for work.

So - PM rolls around and my normally scheduled workout time comes around. My thought was - Now what?

See - I'd done a half assed lowerbody on Tuesday night - so I didn't think I should do a lowerbody last night. (only 24 hr between last lowerbody). And, I'm working on the muscle retention thing/muscle building thing, so I didn't want to spend an hour doing cardio. My choice was to sit on my ass and get a couple extra hours of work in.

But - what's the best protocol there? What would you do if given that opportunity? Would another type of upper body been better - one that worked out different muscle groups than I did in the morning. (like I could have done ab work and lower back and

I typically don't do unscheduled/spontaneous workouts, with the exception of light cardio (which I do consistently throughout the week)

Skip it. You've already done your workout for today.

It's an opportunity