Together with your ex from a long time ago?!?

So I need some feedback here. Four years ago I was with my first real boyfriend and in my first real, mature relationship. We were together for about 9 months until we ended. We were fighting so much that we couldn't be together anymore. Then, about a year ago, he tried sooo hard to get back into my life and get back together with me, but I couldn't let my guard down to let him back in because he really hurt my feelings in the past. Then, around last fall, we became very close friends. We trusted eachother and were extra tight. And then...he got a girlfriend. He seemed so happy with her, I thought they were going to last forever. I was pretty sad when they started going out. I didn't like him, but I didn't want him with anyone else. Normal feelings. Then, he heard that this guy was trying to date me around January time, and I guess he became jealous. He and his girlfriend were on the rocks, and he texted me saying he wanted to catch up. We caught up all right, we started liking eachother real fast. He confessed everything to me: that I was all he ever wanted all along, that he would think about me several times a week even he was dating her, that he never liked her in the first place; he was just seeing if he could be happy with someone else, and he couldn't. Its really an awesome story. So now we are back together and I'm very happy, but I need to know if its normal to feel overwhelmed with all these feelings that came in so fast. Should I be worrying about things happening too fast??? Or, is this all normal?