It is understandable that you are concerned about your relationship with your boyfriend. As you may know, the Bible does not make any allowances for sexual relations outside of marriage; see 1 Corinthians 6:18-7:2.
Scripture condemns immorality as a serious sin because it violates one of the most sacred relationships in life. Sexual relations, stripped of pure love, respect, and a sincere desire to give joy and fulfillment within marriage, become meaningless and unsatisfying.
However, God stands ready to forgive you—totally and completely—for every sin you have ever committed. That may sound impossible—but it is true because of Christ and His love for you. On the cross Christ took your sins upon Himself, and He took the punishment and death you deserve. Turn from your sins, and by faith in Christ receive God's forgiveness and new life: see 1 John 1:9. Then with Christ in your heart, begin to follow Him and His will for your life every day.
While you cannot undo what has been done, you can begin to live a new life. Many who have given up their original virginity are, nevertheless, pledging themselves to virginity from this point forward, until they make a lifetime commitment to the man or woman God leads into their lives. This will mean avoiding occasions of temptation whenever possible.
Playing with temptation is like playing with a deadly poison. The only answer is to turn from it—decisively and finally, not little by little. This is especially true with sexual temptation, which can become so overpowering. We know it will not be easy, but it will be well worth it. God will help you (1 Corinthians 10:13).
We would also urge you to see your doctor immediately to establish whether or not you are expecting a child. If you are, you should counsel with a gospel-teaching pastor before you make the decision as to whether you will keep your baby or place it for adoption in a Christian home. For help in regard to your unplanned pregnancy, please call Care Net at 1-800-395-HELP. Caring people at this organization will be glad to help you.
Be intent on learning God's purpose for your life. Confide in one of your parents or another trusted Christian adult, since their love and concern will provide the guidance and understanding you need during this difficult time of your life. Get involved in a Christ-centered fellowship, and surround yourself with mature Christians to whom you can be accountable.
Try to be faithful in daily Bible reading and prayer as you seek to discover the wonderful plan God has for your life. Jeremiah 29:11 says, "For I know the plans I have for you ... Plans to prosper you and not to harm you, plans to give you hope and a future."