MacBook: woke up to an empty battery, how to get battery history?
Open activity monitor and select energy. It might take a while to crunch the logs, but that should show you some recent history for 12 hours of activity.

I think it offered more time in the past if you were sleeping, but now it seems to only show you a 12 hour clock window.



The command line tool pmset -g log should dump a much more detailed and verbose log of history going back further than 12 hours. You will probably want to process that - perhaps printing only the lines that match the string Charge and then paging the results.

pmset -g log | grep -w Charge | more
pmset -g log | grep -w Summary- | more


Once you see if it slept and how the charge went down, I wouldn't worry about it running hot while closed. I run Mac at high CPU/GPU while closed clamshell all the time (most of the day) and have never had any issues with longevity in practice or overheating - the CPU throttles down when the blowers or heat can't escape due to a blockage or insulation to stay within safe temperature ranges.