It was a brave and important thing for you to do to write us here at PsychCentral. I am very glad that you felt relief from just expressing it.
There are several classic features that suggest it would be good to follow up with therapy. If you felt this good just telling the story, it is likely for some sustainable relief in therapy.
The fact that you have no details of that duplex, the experiences with your brother, the encounter with another little girl, the dreams, flashbacks, and the reality that the man you recalled was arrested for his actions all point to the need to find a way to talk about and heal this time in your life.
My guess is that the impending marriage is stirring the anxiety. Often when we have major role changes, such as becoming a wife, there is a great deal of reflection and review of family roles. As you mature into a more adult role, you may be questioning those adults and circumstances that you’ve experienced.
I would use the find help tab at the top of this page to locate a therapist in your area. I typically recommend an interview with 2 or 3 and decide whom you want to work with. I understand that this may be a difficult thing to do, but just as you felt once you wrote us, therapy may provide an opportunity for more healing.