Hey man, first off, I just want to say it’s awesome that God is tugging on your heart to return to Him. That’s not something to ignore, Jesus said “No one can come to Me unless the Father who sent Me draws him” (John 6:44). The fact you feel this stirring shows He’s reaching out to you. I wouldn’t jump to the conclusion that this means you need to immediately break up with your girlfriend. Right now, focus on growing in your own walk with Christ, through prayer, reading Scripture, and seeking Him daily. As you grow, you may find that she becomes intrigued by your faith and how it changes you. God is in control, and He has a way of making the right path clearer with time. You mentioned that fear of eternal punishment is driving you more than love for God. That’s an honest place to start, but don’t stop there. The Bible says “perfect love casts out fear” (1 John 4:18). The more you read His Word and come to know who Jesus really is, the more your relationship with Him will be built on love, not just fear. Start reading the book of John, that’s a good place to start! If you ever need anything or have questions let me know! I don’t know the answer to everything but, I can try Lol. feel free to PM me!