Honestly, fuck staying at that house. I'm going to be missing my dad's wedding in a few months. I know you have less choice as a minor, but it's very reasonable to need to not be there. I hope that your parents would understand if you tell them, but if not, come up with a lie for now. You deserve to be treated appropriately and to be physically and emotionally safe.
You have several options. Whatever you do is up to you. You could tell someone everything. The pros would be that he could face consequences in some form, you definitely would not have to be in that house, you could open doors to getting support, and you could make the burden a little lighter. If you get to a spot where you can tell someone, I would highly recommend it.
If you can't do that right now, there are plenty of ways to get out of a wedding. I guarantee if you go inpatient for suicidality, they will not let you out for a wedding. I have gone inpatient more than once. It is not a first choice, but that is a guaranteed way to not have to go. They will be able to help you get on antidepressants or antianxiety meds if you want to try them. You can also try an outpatient program to deal with the trauma. They could help you plan how to get out of going to that house.
You could give a half truth. You could say that he made a pass at you and you don't feel comfortable being there. You could also be really sick close to time. You could come up with a lot of different lies. Maybe you could stay with a different family member or friend.
If your body is telling you that you'd rather die than be there, I would listen to it.
I'm so sorry that happened to you. You deserved to be treated appropriately and with respect and I'm sorry you weren't.