Wow, that’s a lot to process. Finding out your dad had kids all over the place is probably shaking up everything you thought you knew about your family. It’s okay to feel confused, angry, embarrassed, or even betrayed right now. Those are all normal reactions to finding out your parent’s life was basically a lie.
Try to remember that this is about your dad’s choices, not about you. You didn’t do anything wrong and this doesn’t change who you are as a person. Your worth isn’t determined by how many half-siblings you have or what your dad did. You’re still you.
You might want to decide if you even want a relationship with these new siblings. Some people find it really meaningful to connect with their extended family. Other people want nothing to do with it because it’s too messy or painful. There’s no right answer here. You get to decide what you’re comfortable with.
Also, your mom probably went through a lot too if she knew about any of this. Maybe talk to her if you can, but be prepared that this might be a sensitive topic. And honestly, consider talking to a therapist because unpacking family trauma like this is not something you should have to do alone. It’s heavy stuff and you deserve support.