A Blessing in Disguise:
We use blessing in disguise when we want to talk about sth that seems bad or unlucky at first, but results in something good or beneficial later.

Examples:
1- Losing my job was a blessing in disguise. It pushed me to pursue my passion for photography, and now I have a successful business doing what I love.
2- My car breaking down on the way to work was a blessing in disguise. While waiting for a mechanic, I met an old friend who offered me a better job opportunity.