The same happens to us when we start learning English. When I asked "please someone teach me which is letter is which, "b" and "d", "f" and "t", "p" and "q"...", I think you can say "just look them carefully" or "please keep learning them again and again", can't you? So I'd like to say "please keep learning until they don't confuse you. Good luck!!!

Are you able to list which ones you get stuck on? I learnt little tricks to learn them. What Kirsten said is a good one for sa and Chi. For ru (る) and ro (ろ) I learnt it as ru has a Ruby in it's tail. But then ru lost it (as r is almost like an 'l' sound the lo from 'lost' gave 'ro' with the 'ruby' missing).

This is something that really bothered me, and sometimes still does. But what helps me is that さ and ちboth looks like the opposite. If you look at ち (chi) it kind of looks like a S (for sa) and on the other hand the buttom part of さ (sa) looks like a c (for chi), so you have to think kind of backwards, but it helped me, maybe it can help you too :) This can backfire a lot too though, so be careful!