I've been seeing this guy for the last few months, at the start we had both said no relationship, but things have changed for me and I'm afraid to say I want a rel in case he freaks out and just ends everything. He only texts me when he wants me to come out, but so do I. even though I want to text him all the time, but just don't him to think I'm clingy, but the last time we spent the whole night together and he said with me he has a great chemistry and I'm different from other girls, he didn't no how to explain it but he said it wasn't love but he had feelings, do you think I could change his mind about the relationship? Because I'm starting to get jelous over other girls and all please help

The two of you might have great chemistry but it doesn't mean he might want a relationship because of it especially if he is seeing other girls. He loves his freedom and no strings attached thing he has going on.

However, you can take the chance and ask him what does he wants because you want more but you can't magically change his mind.

You both wanted just a physical relationship. He has stated that he has feelings, but it's not love. His feelings are in his pants. Your feelings moved, which is exactly what you told him was not going to happen. So he will probably freak out and end everything.
You need to take a look at why your feelings changed.

I would ask him if he would consider pursuing a relationship with you, but don't be heartbroken if he says, "Oh I just want your body."

You walked into that one.