I am sorry, but for my own clarification, this is what happened?

You proposed, and she accepted. You started having fights, and you decided to ease off, so to speak. Your friend convinced you to go back to her, but now you don't feel the same way about her while she is madly in love with you?

I apologize, but I wanted to make sure I have a basic grasp of things before I offer advice.

I would tell you two things right now. As a couple adjusting to such a huge change as proposal, fights are going to naturally happen. That is not at all uncommon. But as far as you not feeling how you used to, I would tell you to give it a little time. If things don't improve, it's not fair to you or her to commit to something as huge as marriage without feeling 100% sure about it.

I hope things work out for you, and I wish you my best.