I have a couple $6 totes from lowes i use when cleaning their enclosure ect.. If you have to run out and buy things I would just turn up your Temp in the house to 75 and keep the aquarium by the heat while you're gone. Your doing good.. Take your time and look at the pics in that link and you will get it all right. Next time your out grab one of these for $5/$6. They lock too. Drill 2 holes in each side for air..
https://m.lowes.com/pd/Hefty-15-Quar...ng-Lid/3341158