Our decision is the result of the connection between reason and emotion. It's always not possible to think rationally. And finding the balance between rational thinking and emotion is a tough job. It's not very unusual also that our emotions win most of the time.
When we can't control some strong emotions like anger or love, we act irrationally. These strong feelings sometimes make us take an unwise decision. But it's not the end of the world. We can learn to make rational decisions and control our emotions.
Don't take any decision when you are facing strong emotions. I think this should be the first rule to deal with this. Our strong emotion makes us narrow, it doesn't let us see the whole thing. So, give yourself time to calm down.
We need to change the process we take a decision. Think about an event when you took a wrong decision and point out what makes you take that decision. What emotions were strong and forced you. What's your fear and insecurity. Then blend it all together, what you need to make a better decision, what you should avoid and what steps you must follow.
Developing a system to think rationally is necessary. As we are very different in person, our thinking process is also very different. So, it's better if you find your own way to deal with your emotions. You can start with a little thing, like daily habits. For example, reducing sugar intake. This gradual effort will bring a change in our thinking process.
Try to see the bigger picture. If you are feeling strong emotions, hold back and wait to calm down. Practicing rational thinking on a daily basis throughout different acts gonna surely make an impact.