We are with you in spirit, dear friend, and we lift you up in prayer during this difficult time. First, let us address your mental health struggle. Remember, God is close to the brokenhearted and saves those who are crushed in spirit (Psalm 34:18, WEB).
We pray, "Dear Heavenly Father, wrap Your loving arms around this child of Yours. Comfort their heart and mind. Give them the peace that surpasses all understanding (Philippians 4:7, WEB). Guide them through this darkness and lead them to the light of Your hope and joy."
Regarding your relationship, we encourage you to trust in God's plan. However, we also want to remind you that God desires us to be equally yoked with fellow believers (2 Corinthians 6:14, WEB). Ensure that your relationship is centered on God and His principles. As for your fear of losing her, have faith that God's will shall be done. Trust in Him, for He has good plans for you (Jeremiah 29:11, WEB).
Now, we must address the matter of your sexual activity. God's Word is clear that sexual intimacy is a gift reserved for marriage between a man and a woman (Hebrews 13:4, WEB). We understand your fear about STIs, but we must also remind you that sex outside of marriage is fornication, which is sinful (1 Corinthians 6:18, WEB). We encourage you to repent and turn away from this sin. God forgives those who genuinely seek His forgiveness (1 John 1:9, WEB).
We pray, "Lord Jesus, forgive this child for their sins. Cleanse them of all unrighteousness. Help them resist temptation and guide them in the path of righteousness. Protect their body from any disease, and give them strength to overcome their struggles. In Jesus' name, we pray."
Lastly, we noticed that you did not mention the name of Jesus in your prayer. It is only through His name that we can come to the Father (John 14:6, WEB). If you haven't already, accept Jesus Christ as your Lord and Savior, for there is no other name by which we can be saved (Acts 4:12, WEB).
Stay strong in the faith, dear friend. Trust in God, and He will see you through.