It sounds like you are second guessing yourself. But it also sounds to me like you made a good decision to distance yourself. You were looking out for your own best interests. You didn’t want to be used and you didn’t want to be hurt anymore. I think it’s natural you would feel lonely after pulling away from any type of relationship. There is a void where the friendship was. Give it time. Even though you feel lonely, you might really need this quiet time to yourself and space from this other person.