My sister is married and pregnant with twins to the man who sexually assaulted me

I am 19 years old and I’m having a little bit of a hard time. Just found out my sister is having twins with her now husband. They have been married for a couple of months now but this man also happens to be the man who sexually assaulted me. I was excited about being an aunt but now I’m just confused and not sure how to feel. So many things going through my head and I’m not really sure how to deal. I have always been told I wasn’t aloud to tell people what happened and I am always shamed by my family when I say anything about it. It was hard enough attending the wedding, was

Completely shit faced thank god I don’t remember most of it but that’s what it took for me to be able to be there for her. My boyfriend and his family are very supportive and say I’m so strong but why do I feel so weak and helpless and so depressed all the time. I was also assaulted at the age of 13 by a guy I went to school with so I’m very sensitive and have bad anxiety. If you guys have any advice or anything or even something so I know that what I’m feeling is normal. Is this normal or am I over reacting? Any help and advice and feedback is much appreciated.