Don't feel bad, this kind of thing happens all the time.
When my sister was getting her drivers license, my dad made her do an oil change on the familly truck for educational purposes. Being the know-it-all that we all were as teenagers, she told us to get lost and she could do it herself. My dad gave her a case of oil and a filter then left her to do the work.
Remarkably she did a pretty good job, drained the oil without making a big mess, got the oil filter off without a wimper, and put the drain plug in without cross threading or stripping the bolt, very good.
When she was done, my dad came out to see an empty case of oil and twelve emptys quarts of oil in the trash...OOPs. Yep she put the whole case of oil in a small block chevy! Dad was pissed!