There's a part of me that loses control. When I'm tired I stop behaving well. After=regret Help?

Meditation will HELP.
Under normal circumstance the mind "control" your action but with the art and the effect of meditation the mind is under controlled by your "mindfulness".
For example- if someone step on your toe (physically) you will spontaneously react with usual habit of reaction (step on him/her; scold, angry, etc) without any thought but if you are "mindful" you have the "gift" of a split of a second to consider your reaction (ignore the incident, maybe give him/her a smile,etc)
Meditation can earn you a lot of such "gifts"