First off, don’t be nervous. Nobody is going to judge you or yell at your or make you feel bad. You’re going to be welcomed back to the church, and people are going to help you make that happen. Heaven rejoices when a sinner repents and God wants you back in the church.
As people said, contact your pastor and get things rolling with him. He will help sort things out.
From your story, if all the facts are true as you presented. Your first marriage will need to be declared null due to lack of form. If you were baptized catholic, and weren’t married in a church or had the first marriage convalidated, it was most likely not valid. Lack of form is easy and you’ll need a baptism certificate and your marriage/divorce papers. If you don’t have those things, they can be obtained, don’t panic.
If your boyfriend has never been married, once you get your nullity decree you can be married in the church validly. There are pre-marriage classes to do first most likely. And if your boyfriend wants to become catholic, he’ll have to go through RCIA.
It might take a while, you’ll have to be patient. But like I wrote, people are there to help you and the church has to deal with cases like this all the time. There are procedures in place to help you along.
Good luck and God Bless!