I feel silly asking this and even more silly to have this problem. I have a android project that has been executing fine until now.
but a couple of days ago, without
Have you checked your run configurations menu? You might have some extraneous configurations in there that Eclipse is defaulting to when you choose to launch the project.
Failing that, there is an option called "Launch in debug mode whenever the workspace contains breakpoints" in the Run/Debug -> Launching preference page. You might want to check to make sure that this option is not enabled.
As a last resort when facing these kinds of quirks I will sometimes create a new project and copy over my source files (provided the project is not very large). Closing and re-launching Eclipse sometimes works wonders for me as well.