I would start by opening and looking over the psalms. They comfort you. Then go to the New Testament, since you need to forgive yourself and know that you are forgiven, and since you are already repenting of what you have done that is weighing on you. Just start at the beginning and read a chapter or two each day.
Here's a good psalm for you today: Psalm 121.
If you are reading from a paper bible that you have on hand, know that the internet also has many translation resources so that a troublesome passage may become clearer in a newer translation. But not all translations are good. For the closest approximation to today's English, I recommend the NEW LIVING Translation (NLT). For beautiful language, the King James Version (KJV). I am not adverse to the New King James, altho some people object. If you are Catholic, there is a standard Catholic Bible, or you could ask some of the FReepers such as Salvation or Mrs. Don-o for advice about what version to use.
There is a site called BibleHub.com where you can type in the verse and you will be shown many translations. But for ordinary online Bible reading of whole chapters, I love BibleGateway.com. It allows you to pick your translation or toggle back and forth between different versions.
Later on you may go back, look at the notes in the New Testament, and you will see that Jesus and the disciples often refer to the verses in the Old Testament, and when you can, go back and read there -- especially Isaiah, which predicts the birth, life, death and resurrection of Christ hundreds of years before it happened.
The most important thing is to just get started somewhere. The fact that you feel bad is the first step! It is repentance and a call out for a savior! He is waiting for you and will speak to you through the words of scripture. Bless you on your journey. Don't hesitate to ask me or any of the intercessors at the AMERICA Prayer Vigil for help via FReepmail, or go to the Religion Forum here on FR and converse with some of the many FReepers who will be glad to help you along your journey, and pray for you. If someone is rude, keep going until you find some FReepers to help and teach you. FReepmail me any time.
Great advice!