Confused with this Leo's behavior

So I've had two of my graduate degree classes with this particular Leo this semester, and will probably continue have classes with him since we just started the degree program. We pretty much hit it off in the beginning, but began talking more and more about a month ago. Honestly, one day we just locked eyes with each other and smiled - then it was like we practically attached at the hip in class.

About three weeks ago we exchanged numbers, and began to text message each other every day. The conversations would last on average 6 hours or more, and it would range from school to our personal life to random things, etc. He's never asked me out, but he's done small things like make sure I didn't open the door and that he wanted to do that for me. He's mentioned he could "never say anything bad about me" and always makes sure that I sit with him. Then once class is over, we walk to our cars together and he'll text me not even a half hour later and we'll talk till we go to bed. I also know that he's mentioned me quite a few times to his best friends, and he'll throw compliments at me every so often. He'll even ask me - especially on weekend nights - what I was up to that night and "if I did anything fun."

Here's the thing that's getting me confused...every now and then over the past week, his responses to our text messages were beginning to lapse to up to an hour and a half. That doesn't bother me considering I have my own life and I'm certainly not expecting us to constantly talk. But all of a sudden on Sunday, he just stopped responding to me and I haven't heard from him since. Granted, he hasn't asked me out and I'm not even sure if that's what I want considering I'm trying to deal with a break-up from a past relationship - which I haven't mentioned, so he doesn't know anything about that. I'm just wondering if I did something wrong or is this how all Leos act? I just find it strange how we went from constant contact to nothing at all.

Oh, and by the way, I'm a Gemini. I don't know how much that'll play into details, but I figured I'd throw that in there too.

Thanks!

Oh Gemini and leo are fun together.

Its been the lead up to Xmas and everybody is busy and has lots on their plate......Id suggest just getting on with your life and wait til he comes back...you mentioned you will be taking classes together - he hasnt disappeared as such and sometimes us Leos want and need space from others.

Perhaps he also has issues to solve through from a past relationship...its too early to even worry and from a lot of experience now....its not worth worrying LOL