I have Unwanted Thoughts how can I control them?

It's great that you realise they are unwanted, that is a good first step! It's less about controlling the thoughts and more about letting go of the hold they have on you. It's okay to have things pop up in your mind, but punishing yourself for having them will make you feel a lot worse. Try taking a breathe, recognising where the thought comes from, allowing into your mind and slowly breathing it back out. You can eventually train yourself to get rid of the thought a lot quicker as you recognise it and accept it with less frustration and continue your focus on your breath.