Sometimes when trying to follow practices like partial fasts on Ekadashi or meditating every day during certain periods, something happens that disrupts the practice, and I would like to know the best course of action when this happens.
For example, on one Ekadashi while trying to fast grains I ate a Pringle thinking it was like a potato chip, then realised there's flour in it. Recently I promised myself I'd meditate every day through Chaturmasya, but one evening I fell asleep while trying. This week I'd considered lighting a lamp each night of Adhik Maas and resuming the meditation, although hadn't decided completely. In the end I didn't last night but now wish I had, and am thinking about starting tonight but am worried that even genuine devotional practice for the rest of the month wouldn't count.
My question isn't so much about any of these individual situations as the theme running through them. What should be done when we stumble? Is it worse to try and fail than not to try at all? And if we do, what should we do about it?
(Am particularly interested if there are any Gita references that address this but would be grateful to hear if it is addressed in any Hindu texts, or just people's thoughts based on their knowledge and experience.)