The price one has to pay for not having the presence of mind under life changing circumstances is enormous and in many cases pivots ones life in the wrong direction. Sleeping , Exercising well is not a challenge when you have a chill life but those are the things that are the hardest to consistently keep up with during important/time critical situations (E.g. Interviews , meetings ) .Venting out but also looking for opinions on how to always have a good presence of mind to avoid "crying over spilled milk" situations.
Prioritize sleep and diet. These are real needs. Stress only exists in your head, it's not material.
+1 to what bFCN68 said. Meditation helps too.