How can you tell when you are EXTREMELY tilted?

I'm not the usual type of person to go on tilt, I usually stay pretty calm and chill. Yesterday was the first time I've ever actually experienced real tilt..

I realized it when I had like 30cs at almost 20 minutes as . I was so tilted that I couldn't even last hit. I'm not proud to say that I had to leave that game for fear of breaking my keyboard, or maybe even more.

It all started with me stopping playing yesterday, I realized it was a bad day for me to be playing league, but some of my friends was like "c'mon man just play, we'll win and put you in a better mood".. So I decided to hop back on.. Worst decision I've ever made..

It started well, a great game of League going 40+ minutes. Both teams playing well, and it simply came down to who had the better teamwork/skill. How it should be. We ended up winning after we aced them at baron. Fun game where I played .

Then with losing a 4v5 game, us being the 5. Our decided to feed the , and our decided to feed . So they just all snowballed to victory. I was trying some more, so there was nothing I could have really done to carry us. Still learning that weird-ass champ.

Then came the EXTREME TILT... Playing against a and .. This is the game I speak of above. This is when I realized how tilted I was, and what its like playing tilted. It's a horrible experience. I couldn't last hit, was paying no attention to anything, and making horrible decisions. This is when it hit me, "I'm tilted". Real tilt.

TL;DR How can you guys tell when you are tilted? How do you deal with it? Is there anyway to break out of what I mentioned above without actually just stopping playing?