Katarina's Damage

I've started playing mid recently and i've been able to play like 10 games in a row with yasuo and talon and such mids. I went against a katarina i think 8 times out of 10 and i've been noticing somethings...

Why is katarina so broken?

Some may say i'm bad and i would answer YES i'm the worst mid... But i crush others in my level range when i play alone (i'm lvl 30 unranked and play with plats and diamonds) But i've never been able to even scratch a katarina and i have never won against any katarina in any game what so ever.

Her passive is wayyyy to strong why the hell will you give this god forsaken ult back to her when she has a kill? It's a garenteed pentakill when she gets a single one.

And her little throwing knife does way too much damage for this type of spell. I mean we've seen this type of spell on lots os other champs before and it does less than half of it on the most part.

3/4 of the time, katarina kills me with her jump and her spin. The other quarter of the time she just plains one shot me with her spins. (litterally)

Trust me... Death recap never lies to you...

When it says 2135 damage in 1 hit by katarina's spin or whatever it's called... That should ring some bells somewhere...

I would like people to read this and give me their thoughts on katarina (when they're against her)

Thank you for reading this.