Why is this causing me so much stress?

If you want to give maximum advice and get 10 points, then Please read one of my many other questions about my 'crush', as I suspect this might have something to do with it.

Okay, here's the story.Me, my friend, my other friend who has a crush on my friend, and my crush were organising a horror movie marathon (this is where you might want to know more about how me and my crush interact) for one Saturday, and I was really excited. Just the four of us, snacks and 10 hours worth of the Halloween series. To be honest I still don't know if my crush is coming, she seems to want to but she hasn't checked the group chat on Facebook in ages, so we can't really plan it.

Just today, my friend put a message on the group chat asking if her friend can come to the marathon, and I really don't want her to. No one else really knows her, so I messaged the guy I'm organising it with, pretty much saying "Listen Lewis (the guy friend), Natasha (the girl who has a crush on Lewis) wants her friend to come to the marathon. Personally I'm against the idea. Neither me, you or Natalia (the girl I have a crush on, she's Polish [hence the name]) actually know her. So when you see this, reply with what you think mate". He replied with "hmm, not sure, I'll talk to Natasha." Now this is when I started getting stressed (and I have NO idea why). She probably won't interfere with me and my crush, I guess I just like the idea of it being a small group. As far as I know I don't have any strange phobias, I never mind open crowds and when I'm in the city centre I usually invite lots of friends to chill with.

Now THIS is where you might have to have some kind of psychology training to understand what's going on with me. When I think of how soft my crush is, I feel better. Now I bet you're sat there thinking "who IS this freak?!" Well to avoid confusion and/or hate, allow me to explain.
One break-time at school, I was hanging out with Lewis, Natasha and Natalia. I was showing pictures on my phone. I do this a lot because Natasha and Natalia tend to get in close and look because I have an iPhone, and for some STUPID reason they seem to be jealous. Then, I noticed Natalia pressing up to my right side, looking at my phone. She was wearing a pretty thick winter coat and scarf, so she probably didn't know she was doing it. She was just standing, with her FRONT side pressing against me, protected by a comfy winter coat. However when I think of how soft it felt, the stress about this extra girl coming to the marathon goes away, and I'm suddenly feeling all warm with love, over this ONE thing. It's really confusing me.

So, if by some miracle you have some kind of experience with psychology, could you please explain to me why I feel better when I think about the break-time incident? It's probably just because I'm a teenager, and my moods are all over the p;ace, and this whole question is probably just me being a drama queen anyway, but I just really want some closure.

Sounds chiefly like teen hormonal changes run amok to me.