Yikes, if you or someone else isn't there to do your 25% minimum water changes daily, your fish will probably be dead by the time you come home. If you aren't super attached to the three fish you have (a betta and two tetras, right?) you should take them back to your fish store for a future credit and do a fishless cycle with your tank. It will be much easier on the fish, and you.
Edited to add - you don't have to change water daily once your tank has re-established itself through a new cycle. But right now, your tank is extremely sensitive and needs daily maintenance to preserve the lives of your fish.