My biggest problem :)

My biggest problem is the next one.

I make my moves too quickly.

And very often immediately after I did it, I see that I made a mistake.

In the next game I had a lost position just before my opponent made two really big mistakes one after the other.

First one I saw and was so glad that after his second made my biggest mistake.

I understood it immediately after my wrong move, but it was too late

How to learn myself to think before a move, not after?