sidetrapped
When you start a task and then see something else that needs done and you are triggered to go on and do THAT OTHER task ; while still intending to complete the first task you started...but you can't now because you ran out of time.
I got totally SIDETRAPPED into doing that sewing project ! I sat down and started painting those mason jars, looked up and decided I needed to sew those curtains up as well....so I never finished the jars :-(