Compassion is a trait that may seem far fetched when talking fitness, health and wellness goals, I however place it highest of all.
Achieving our goals very rarely happens in a linear fashion. There are a number of stumbling blocks, pitfalls, detours and blocks that one may encounter.
The cause or source of the derail is good for the learning process. You will learn what triggers the undesirable behaviour and possibly how to stay clear or better deal with the triggers.
Compassion is definitely not a pity party. There is no point at all in wallowing in sorrow about falling of the band wagon. Best you remeber your why, understand that you make mistakes and move on from that.
No matter the size of the mistake, see it as just a part of your journey.
Go easy on yourself.