P5R was easy until now

I've been breezing my way through this game and thoroughly enjoying it!

But now, I don't think I'm going to be able to finish it which is so depressing.

I just cannot get past the Okumura battle at all! I can get through the first 4 waves then the fifth wave takes me out or the big ass robot needs me! It sucks so much, I was so invested and now I'm just at a complete standstill.