OP if you search any other airline forum you will find out you arent alone.

Heck search VS and you will find the thread where I ran into tehs ame problem, but VS didnt offer me anything at 1st, when they finally came around to it I said Thanks but No Thanks , it was the principle that they should have offerred something. Not for my bag not being on my flight but for how they messed up after that

UA will probably throw a bone your way thats alot more then most Carriers will do And at least hopefully UA didnt have their guy banging on your door and ringing the bell as if the house was on fire @ 11:45pm like in my case

but as others have posted already always have at least what you need for 1 or 2 days in your carry-on