I am more or less in this rut now. I do SW planning which I now will be impossible to meet. Hopefully we never hit the deadline because priorities, requirements and resources constantly change. So planning is always revised. I am not the only one in this game. One rule I learnt is to never tell the plan cannot be realized. When this is all too obvious though, I let more experienced coworkers handle the situation with appropriate business speak I am far from mastering yet. Kind of a strange situation for an engineer.