My prayers will be with you. There’s not many worse situations to be in than the one you’re in right now.
I would like to suggest to you that for now, find a traditional looking Catholic church (one that looks like
this or
this, as opposed to
this or [this](
http://www.cityknown.com/Ma(name removed by moderator)hotos/003/Attractions/1541755549615820.jpg)), and spend some time on your knees praying. Look for the red candle, as the blessed Eucharist, what Catholics believe to be the body, blood soul and divinity of Christ, is traditionally laid in repose in a tabernacle very close to the red candle. I think you’ll find the experience quite illuminating.
Drop the “Dear Heavenly Father, we thank you for this nice day” rote Mormon prayer and just speak from your heart. Tell God your fears, and your love for Him, and your desire to do his will. Ask for his guidance, and thank him for his grace in the precious blood of his Crucifixion. As a Mormon, I’m sure you haven’t had a lot of experience with mediating on Christ’s passion, but simply looking at a beautiful cross can help with understanding what it is that Christ actually did for us when He was here. Then just sit there, quietly, in His presence and listen for a while. That part is the hard part for me and I’m nowhere near as good at it as I’d like to be, but it’s very important. And it’s not something I learned from being a Mormon.
I’ll keep you in my prayers - you have an amazingly difficult journey coming up.