В субботу я отрезал манго и съел одну половину, она была чистой. Отрезал вторую половину, съел, и только потом заметил, что там черви, после чего выплюнул. Что мне делать?

If you accidentally ate worms in fruit or mango, bishogeg, unintentionally, there's no punishment of malkot for this. Why? Because Hashem is not going to punish you for something you couldn't see or didn't know was there. The Gemara teaches us HaRachaman Poteir Onusim - the Merciful One exempts those who act under duress or without knowledge. However, understand this clearly: even though there's no punishment in the form of malkot when it's truly accidental, it still causes spiritual damage to your neshama. When you eat non-kosher things, even bishogeg, it affects your soul and creates a certain level of tumah, impurity. The Torah and Gemara explain that eating bugs can make a person spiritually foolish, affecting your emunah and your connection to Hashem. What should you do now? Make teshuva. Recognize what happened, feel genuine regret, and commit to being more careful going forward. This is not the end of the world if you forgot once - do teshuva and move forward. More importantly, take steps to prevent this from happening again. You need to properly check and wash all fruits and vegetables before eating them. This is not optional - it's halacha. Put the fruit or vegetables in a bowl with soap water, leave them for several minutes, rinse them thoroughly, and inspect them carefully. For leafy vegetables, you need to wash them multiple times with salt or soap water to make sure all the bugs are removed. Every time you eat a worm or bug, it's like eating pig five or six times - it's multiple sins from the Torah. So even though your mistake was accidental, you must take this seriously going forward. Learn how to properly clean your produce, and don't be lazy about it. Your neshama depends on it.