Life is made out of experiences. They are completely neutral and you determine what label to put on them. There is no such thing as negative, nothing that happens to you is bad. Everything that happens to you right now is the best thing for your growth and development. The only reason it makes you feel bad is simply that you do not believe it is so. The only thing that is the source of how you feel is your perception of it. If you could see the reality before you with clarity, you wouldn't suffer at all.
So how do you perceive something as negative? You might not be aware of it, but the moment something happens you put a label on it and see it through the lense of that label. An event A happens to you and you might unconsciously think:
"I do not want this to happen."
"This is not benefitial for me."
"That is the worst thing that could possibly happen to me."
All the negative emotions come from these thoughts and not from the event itself. Thoughts determine your perspective and if you want to change it you simply have to change your thoughts. When something that you perceive as negative happens simply think repeatedly:
"My life is taking care of me."
"That is the best thing that could have ever happened to me."
"Life is on my side."
"What a fortunate turn of events."
You can make your own affirmations along those lines.
Every time something unexpected, or unpleasant occurs, do it. You can also use them for events in your past, or when something pleasant occurs. It works both ways. This requires minimal effort and if you are consistent you will be staggered by the results and the transformation that has happened in your life.
Wishing you joy & success