Furthermore, practice and expand your champion pool. I just realized that you only had 80 CS at the end of that game, which was what, 32 minutes long? Better CSing would have at least had you with another item or two.
I guess what I'm trying to say is that if you performed better on an individual basis, you wouldn't have had as many problems. When you play better have more farm, more items, better positioning, better vision, you typically can deal with the fact that Yi is strong even if you don't have direct counters or a lot of hard CC. You guys were actually positioned to be able to deal with that Yi, Taric has a point and click stun, Karma has a snare which she can start immediately upon stun to more likely hit the snare, Caitlyn has a snare, though much harder to hit, she still has it, Lee could have kicked him away. There was a lot more there than was being utilized properly, and that's where the experience of players comes into account. A more experienced group of players could have properly utilized the CC to lock down Yi before he got so big.
I would have liked to have seen a Zhonyas built early as soon as you realized that Yi would be a problem. I don't particularly like the Morellonomicon pickup on Fizz, he doesn't really need mana regen, so much as just a larger mana pool, which Lichbane solves for the most part, the rest is about learning to manage your mana. Fizz is also really difficult to properly utilize now as a mid laner, I genuinely don't suggest playing him in mid lane when you're relatively new to the game.
You also NEED to work on warding big time, when I get to play mid lane, I typically have at least 2 wards down on the map, that's my pink and my trinket ward. When my trinket is on CD and just expired from the map, I'm usually looking to back ASAP so I can buy more wards and get some items to increase my strength in lane. If you were to look at my last 5 games played on SR, you'd see that I have high warding scores in most of those games, my recent Kassadin game I was a touch lazy, but with how safe he was I could get away with it. Stealth wards are only 75g, there's basically no reason not to buy them, delaying an item is fine if it means you're much less likely to die, I've had several games where wards not only prevented my death, but caused me to gain gold because I saw an enemy coming. In my last 5 SR games, I've died 3 times. So where a lot of people may see my warding habits as a waste of money, I see them as the reason I have a 28.3 KDA over my last 5 games.
problem solved
was for grievous wounds, not mana regen since Yi's Q took him from 20% health back to full on top of his W tanking what should have been our burst damage.
would have been good choices.