I once read that it does not come down to "good" and "bad" decisions necessarily; just choices, with consequences that may or may not be desirable to you. I think that perspective can be really powerful; treat them for what they are, decisions.
Instead of getting after yourself for not making it to the gym that day, recognize and congratulate yourself other types of movement you did fit it. Maybe you took a walk on your lunch break or made time to roll around and play with the kids. Maybe you pushed through the yard work that needed to be done. Those are all great things too!