Mindfulness is a translation of a Buddhist term that generally means "recollection" or "remembrance". It can be used in any number of ways, for example "recollection of the Buddha", "recollection of past lives", etc. In insight meditation, it refers to one's ability to recollect or remember the present moment, as taught in the discourse on the four foundations of mindfulness.
The four foundations are
- body - recognizing and reminding oneself of bodily sensations as being simply bodily sensations
- feelings - recognizing and reminding oneself of feelings (pain, pleasure, neutral) as being simply feelings
- mind recognizing and reminding oneself of one's state of mind (scattered, focussed, etc.) as being simply a state of mind
- dhammas - recognizing and reminding oneself of various aspects of ones experience on the path to enlightenment as being simply what they are.
So, to answer your question, mindfulness is simply a tool used to focus one's attention on a specific object; what you are suggesting sounds like a conceptual object, e.g. something unrelated to the task at hand to take your mind off of the present moment. This could be called "mindfulness", in the sense that you are actively working to recollect a specific object. It would be considered a form of samatha (tranquility) meditation, since it is no longer based on ultimate (i.e. present moment) reality.
The problem with what you suggest is that it seems to likely involve aversion to the present moment, and so it is not likely to lead to true freedom from the suffering associated with aversion. For this, you will need to practice mindfulness as described above regarding the four foundations. There, it should be used to focus on the present moment and remind you that the stress you feel is merely stress - not me, not mine, not good, not bad, etc.
A Buddhist perscription for your condition would be to focus your attention on the state of being flustered, as such states are conditioned by habit and can be countered with new conditioning (i.e. objectivity) through simply recognizing them as they are. As the Buddha said, for example:
idha, bhikkhave, bhikkhu sarāgaṃ vā cittaṃ ‘sarāgaṃ cittan’ti pajānāti
Here, bhikkhus, a bhikkhu clearly knows a mind with passion thus: "a mind with passion".
-- MN 10
In my tradition, this is accomplished by noting the flustered mind, for example, as "flustered, flustered..." somewhat akin to a mantra.