These thoughts maybe transient, yet it will feel real when it occours in the mind.
Our mind is like storage for the memory,from that nature of thoughts will be, some maybe pleasant some disturbing. It all depends on the event happened in our life.
Gif source
The worst thing about this is we feel like we are chained to a certain events, which keeps repeating in our mind.
Like there's no escape but there is.
We cannot fight with our mind nor control it but we can do one thing which will make the thoughts settled and less effective, that is to be AWARE. Just watch how it plays in your mind and know that its not real and it will go.
While thinking about this topic, i came across such a movie( The voices 2014) which had a scene dealing with it.
Let me post the the lines from it.
Jerry :why do I hear voices?
Dr Warren: Oh, a lot of people hear voices. Or thoughts they can't stop.
Jerry : A lot of people?
Dr warren : Yeah. It might be a voice telling them they're worthless or stupid or...
or it could tell them to indulge every desire... drink that drink, take that drug,
follow every sexual impulse.
Or it could be a cynical voice
telling them nothing matters.that their efforts are insignificant.
Jerry :You hear stuff like that?
Dr warre: Yeah.
I have thoughts.
Not exactly the same as you, but similar. They tell me that I'm fat or psychotherapy is... is not a worthwhile exercise,
that... that it's not real, that I should've aimed higher than a government job,
that my potential is being squandered, that I'm unworthy of love.
Jerry :But none of that's true.
So what do you do about it?
Dr warren : Well, I can't shut them off entirely...
nor would I want to... but I can argue against them.
Just because you have thoughts doesn't mean you have to act on them.
Jerry: You don't have to act on them?
Dr : No.
Or you can the watch the full scene here