WTF is Leblanc

i never played against a lb in a game before and i just want to know why riot made her so unbalanced. i just went into a game against her as vel cos. i know this match up very well with the old lb so i was not too worried but when we just got in, we farmed for a few sec and once she got lvl 2 she all in and faster that i can react i still put barrier but the damage she put out went right through it and killed me (this was not one of those, i got pocked and then all in, this was a full hp, 2 abilities one shot in a matter of 2 seconds). how can this happen? level 2 lb insta killed me and even my team saw it and was like wtf. then i went back into lane and then out of no where a lb jumps out of fog of war into my tower and insta kills me again. how can this be allowed??? she was only lvl 3 or 4 by the time i got back and does that. i did not even get a chance to reach my lane so i was still lvl 2 without a e. this is so stupid please we need to either nerf her hard so she will be as strong as the old lb or just turn her back.